diff --git a/htdocs/adherents/class/api_members.class.php b/htdocs/adherents/class/api_members.class.php
index 6fad266ea36..d30e851b9a2 100644
--- a/htdocs/adherents/class/api_members.class.php
+++ b/htdocs/adherents/class/api_members.class.php
@@ -358,7 +358,7 @@ class Members extends DolibarrApi
 		if ($member->update(DolibarrApiAccess::$user) >= 0) {
 			return $this->get($id);
 		} else {
-			throw new RestException(500, $member->error);
+			throw new RestException(500, 'Error when updating member: '.$member->error);
 		}
 	}
 
diff --git a/htdocs/adherents/class/api_memberstypes.class.php b/htdocs/adherents/class/api_memberstypes.class.php
index be8f22f3c45..d95de755166 100644
--- a/htdocs/adherents/class/api_memberstypes.class.php
+++ b/htdocs/adherents/class/api_memberstypes.class.php
@@ -204,7 +204,7 @@ class MembersTypes extends DolibarrApi
 		if ($membertype->update(DolibarrApiAccess::$user) >= 0) {
 			return $this->get($id);
 		} else {
-			throw new RestException(500, $membertype->error);
+			throw new RestException(500, 'Error when updating member type: '.$membertype->error);
 		}
 	}
 
diff --git a/htdocs/adherents/class/api_subscriptions.class.php b/htdocs/adherents/class/api_subscriptions.class.php
index 55b93df7663..f969017146b 100644
--- a/htdocs/adherents/class/api_subscriptions.class.php
+++ b/htdocs/adherents/class/api_subscriptions.class.php
@@ -159,7 +159,7 @@ class Subscriptions extends DolibarrApi
 			$subscription->$field = $value;
 		}
 		if ($subscription->create(DolibarrApiAccess::$user) < 0) {
-			throw new RestException(500, 'Error when creating subscription', array_merge(array($subscription->error), $subscription->errors));
+			throw new RestException(500, 'Error when creating contribution', array_merge(array($subscription->error), $subscription->errors));
 		}
 		return $subscription->id;
 	}
@@ -193,7 +193,7 @@ class Subscriptions extends DolibarrApi
 		if ($subscription->update(DolibarrApiAccess::$user) > 0) {
 			return $this->get($id);
 		} else {
-			throw new RestException(500, $subscription->error);
+			throw new RestException(500, 'Error when updating contribution: '.$subscription->error);
 		}
 	}
 
diff --git a/htdocs/api/class/api_documents.class.php b/htdocs/api/class/api_documents.class.php
index 28dbef6887e..da49e4cbba7 100644
--- a/htdocs/api/class/api_documents.class.php
+++ b/htdocs/api/class/api_documents.class.php
@@ -126,7 +126,7 @@ class Documents extends DolibarrApi
 	 * @param	string	$langcode		Language code like 'en_US', 'fr_FR', 'es_ES', ... (If not set, use the default language).
 	 * @return  array                   List of documents
 	 *
-	 * @throws RestException 500
+	 * @throws RestException 500 System error
 	 * @throws RestException 501
 	 * @throws RestException 400
 	 * @throws RestException 401
@@ -249,7 +249,7 @@ class Documents extends DolibarrApi
 	 * @throws RestException 400
 	 * @throws RestException 401
 	 * @throws RestException 404
-	 * @throws RestException 500
+	 * @throws RestException 500 System error
 	 *
 	 * @url GET /
 	 */
@@ -546,7 +546,7 @@ class Documents extends DolibarrApi
 	 * @throws RestException 400
 	 * @throws RestException 401
 	 * @throws RestException 404
-	 * @throws RestException 500
+	 * @throws RestException 500 System error
 	 *
 	 * @url POST /upload
 	 */
diff --git a/htdocs/comm/propal/class/api_proposals.class.php b/htdocs/comm/propal/class/api_proposals.class.php
index 41ed388e044..2cc17987224 100644
--- a/htdocs/comm/propal/class/api_proposals.class.php
+++ b/htdocs/comm/propal/class/api_proposals.class.php
@@ -533,7 +533,7 @@ class Proposals extends DolibarrApi
 	  *
 	  * @throws RestException 401
 	  * @throws RestException 404
-	  * @throws RestException 500
+	  * @throws RestException 500 System error
 	  */
 	public function deleteContact($id, $contactid, $type)
 	{
@@ -707,7 +707,7 @@ class Proposals extends DolibarrApi
 	 * @throws RestException 304
 	 * @throws RestException 401
 	 * @throws RestException 404
-	 * @throws RestException 500
+	 * @throws RestException 500 System error
 	 *
 	 * @return array
 	 */
diff --git a/htdocs/commande/class/api_orders.class.php b/htdocs/commande/class/api_orders.class.php
index 48865f958a2..fb912139d5f 100644
--- a/htdocs/commande/class/api_orders.class.php
+++ b/htdocs/commande/class/api_orders.class.php
@@ -574,7 +574,7 @@ class Orders extends DolibarrApi
 	 *
 	 * @throws RestException 401
 	 * @throws RestException 404
-	 * @throws RestException 500
+	 * @throws RestException 500 System error
 	 */
 	public function deleteContact($id, $contactid, $type)
 	{
@@ -704,7 +704,7 @@ class Orders extends DolibarrApi
 	 * @throws RestException 304
 	 * @throws RestException 401
 	 * @throws RestException 404
-	 * @throws RestException 500
+	 * @throws RestException 500 System error
 	 *
 	 * @return  array
 	 */
@@ -974,7 +974,7 @@ class Orders extends DolibarrApi
 	 *
 	 * @throws RestException 401
 	 * @throws RestException 404
-	 * @throws RestException 500
+	 * @throws RestException 500 System error
 	 */
 	public function getOrderShipments($id)
 	{
@@ -1030,7 +1030,7 @@ class Orders extends DolibarrApi
 	 *
 	 * @throws RestException 401
 	 * @throws RestException 404
-	 * @throws RestException 500
+	 * @throws RestException 500 System error
 	 */
 	public function createOrderShipment($id, $warehouse_id)
 	{
diff --git a/htdocs/compta/facture/class/api_invoices.class.php b/htdocs/compta/facture/class/api_invoices.class.php
index 8282610d01d..61f0a9e8d15 100644
--- a/htdocs/compta/facture/class/api_invoices.class.php
+++ b/htdocs/compta/facture/class/api_invoices.class.php
@@ -507,7 +507,7 @@ class Invoices extends DolibarrApi
 	 *
 	 * @throws RestException 401
 	 * @throws RestException 404
-	 * @throws RestException 500
+	 * @throws RestException 500 System error
 	 */
 	public function deleteContact($id, $contactid, $type)
 	{
@@ -649,7 +649,7 @@ class Invoices extends DolibarrApi
 
 		$result = $this->invoice->delete(DolibarrApiAccess::$user);
 		if ($result < 0) {
-			throw new RestException(500);
+			throw new RestException(500, 'Error when deleting invoice');
 		}
 
 		return array(
@@ -768,7 +768,7 @@ class Invoices extends DolibarrApi
 	 * @throws RestException 304
 	 * @throws RestException 401
 	 * @throws RestException 404
-	 * @throws RestException 500
+	 * @throws RestException 500 System error
 	 *
 	 */
 	public function addContact($id, $fk_socpeople, $type_contact, $source, $notrigger = 0)
@@ -817,7 +817,7 @@ class Invoices extends DolibarrApi
 	 * @throws RestException 304
 	 * @throws RestException 401
 	 * @throws RestException 404
-	 * @throws RestException 500
+	 * @throws RestException 500 System error
 	 *
 	 */
 	public function settodraft($id, $idwarehouse = -1)
@@ -920,7 +920,7 @@ class Invoices extends DolibarrApi
 	 * @throws RestException 304
 	 * @throws RestException 401
 	 * @throws RestException 404
-	 * @throws RestException 500
+	 * @throws RestException 500 System error
 	 */
 	public function settopaid($id, $close_code = '', $close_note = '')
 	{
@@ -970,7 +970,7 @@ class Invoices extends DolibarrApi
 	 * @throws RestException 304
 	 * @throws RestException 401
 	 * @throws RestException 404
-	 * @throws RestException 500
+	 * @throws RestException 500 System error
 	 */
 	public function settounpaid($id)
 	{
@@ -1057,7 +1057,7 @@ class Invoices extends DolibarrApi
 	 * @throws RestException 304
 	 * @throws RestException 401
 	 * @throws RestException 404
-	 * @throws RestException 500
+	 * @throws RestException 500 System error
 	 */
 	public function markAsCreditAvailable($id)
 	{
diff --git a/htdocs/don/class/api_donations.class.php b/htdocs/don/class/api_donations.class.php
index 597f15b7f10..f9af0568bf0 100644
--- a/htdocs/don/class/api_donations.class.php
+++ b/htdocs/don/class/api_donations.class.php
@@ -293,7 +293,7 @@ class Donations extends DolibarrApi
 	 * @throws RestException 304
 	 * @throws RestException 401
 	 * @throws RestException 404
-	 * @throws RestException 500
+	 * @throws RestException 500 System error
 	 *
 	 * @return  array
 	 */
diff --git a/htdocs/expensereport/class/api_expensereports.class.php b/htdocs/expensereport/class/api_expensereports.class.php
index df942ff93e6..37319a3ec71 100644
--- a/htdocs/expensereport/class/api_expensereports.class.php
+++ b/htdocs/expensereport/class/api_expensereports.class.php
@@ -401,7 +401,7 @@ class ExpenseReports extends DolibarrApi
 	 *
 	 * @throws	RestException	401		Not allowed
 	 * @throws  RestException	404		Expense report not found
-	 * @throws	RestException	500
+	 * @throws	RestException	500		System error
 	 */
 	public function put($id, $request_data = null)
 	{
diff --git a/htdocs/fourn/class/api_supplier_invoices.class.php b/htdocs/fourn/class/api_supplier_invoices.class.php
index 06c836b4d77..35e783729ff 100644
--- a/htdocs/fourn/class/api_supplier_invoices.class.php
+++ b/htdocs/fourn/class/api_supplier_invoices.class.php
@@ -211,7 +211,7 @@ class SupplierInvoices extends DolibarrApi
 	 * @return int  ID of supplier invoice
 	 *
 	 * @throws RestException 401
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 */
 	public function post($request_data = null)
 	{
@@ -283,7 +283,7 @@ class SupplierInvoices extends DolibarrApi
 	 *
 	 * @throws RestException 401
 	 * @throws RestException 404
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 */
 	public function delete($id)
 	{
@@ -300,7 +300,7 @@ class SupplierInvoices extends DolibarrApi
 		}
 
 		if ($this->invoice->delete(DolibarrApiAccess::$user) < 0) {
-			throw new RestException(500);
+			throw new RestException(500, 'Error when deleting invoice');
 		}
 
 		return array(
@@ -326,7 +326,7 @@ class SupplierInvoices extends DolibarrApi
 	 * @throws RestException 401
 	 * @throws RestException 404
 	 * @throws RestException 405
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 */
 	public function validate($id, $idwarehouse = 0, $notrigger = 0)
 	{
diff --git a/htdocs/fourn/class/api_supplier_orders.class.php b/htdocs/fourn/class/api_supplier_orders.class.php
index e21eb3436dc..d55a398dbd6 100644
--- a/htdocs/fourn/class/api_supplier_orders.class.php
+++ b/htdocs/fourn/class/api_supplier_orders.class.php
@@ -309,7 +309,7 @@ class SupplierOrders extends DolibarrApi
 		}
 
 		if ($this->order->delete(DolibarrApiAccess::$user) < 0) {
-			throw new RestException(500);
+			throw new RestException(500, 'Error when deleting order');
 		}
 
 		return array(
diff --git a/htdocs/product/class/api_products.class.php b/htdocs/product/class/api_products.class.php
index ec735da3865..0f21b2aac3c 100644
--- a/htdocs/product/class/api_products.class.php
+++ b/htdocs/product/class/api_products.class.php
@@ -742,7 +742,7 @@ class Products extends DolibarrApi
 	 * @param  	int		    $fk_barcode_type     	        Barcode type
 	 * @return int
 	 *
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 * @throws RestException 401
 	 *
 	 * @url POST {id}/purchase_prices
@@ -1158,7 +1158,7 @@ class Products extends DolibarrApi
 	 * @param  string $ref_ext External reference of Attribute
 	 * @return array
 	 *
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 * @throws RestException 401
 	 *
 	 * @url GET attributes/ref_ext/{ref_ext}
@@ -1206,7 +1206,7 @@ class Products extends DolibarrApi
 	 * @param  string $ref_ext   Reference of Attribute
 	 * @return int
 	 *
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 * @throws RestException 401
 	 *
 	 * @url POST attributes
@@ -1283,7 +1283,7 @@ class Products extends DolibarrApi
 	 * @param  int $id 	ID of Attribute
 	 * @return int		Result of deletion
 	 *
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 * @throws RestException 401
 	 *
 	 * @url DELETE attributes/{id}
@@ -1311,7 +1311,7 @@ class Products extends DolibarrApi
 	 * @param  int $id ID of Attribute value
 	 * @return array
 	 *
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 * @throws RestException 401
 	 *
 	 * @url GET attributes/values/{id}
@@ -1352,7 +1352,7 @@ class Products extends DolibarrApi
 	 * @param  string $ref Ref of Attribute value
 	 * @return array
 	 *
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 * @throws RestException 401
 	 *
 	 * @url GET attributes/{id}/values/ref/{ref}
@@ -1439,7 +1439,7 @@ class Products extends DolibarrApi
 	 * @return array
 	 *
 	 * @throws RestException 401
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 *
 	 * @url GET attributes/{id}/values
 	 */
@@ -1511,7 +1511,7 @@ class Products extends DolibarrApi
 	 * @param  string $value Value of Attribute value
 	 * @return int
 	 *
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 * @throws RestException 401
 	 *
 	 * @url POST attributes/{id}/values
@@ -1545,7 +1545,7 @@ class Products extends DolibarrApi
 	 * @return array
 	 *
 	 * @throws RestException 401
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 *
 	 * @url PUT attributes/values/{id}
 	 */
@@ -1590,7 +1590,7 @@ class Products extends DolibarrApi
 	 * @param  int $id ID of Attribute value
 	 * @return int
 	 *
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 * @throws RestException 401
 	 *
 	 * @url DELETE attributes/values/{id}
@@ -1617,7 +1617,7 @@ class Products extends DolibarrApi
 	 * @param  int  $includestock   Default value 0. If parameter is set to 1 the response will contain stock data of each variant
 	 * @return array
 	 *
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 * @throws RestException 401
 	 *
 	 * @url GET {id}/variants
@@ -1653,7 +1653,7 @@ class Products extends DolibarrApi
 	 * @param  string $ref Ref of Product
 	 * @return array
 	 *
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 * @throws RestException 401
 	 *
 	 * @url GET ref/{ref}/variants
@@ -1695,7 +1695,7 @@ class Products extends DolibarrApi
 	 * @param  string $ref_ext External reference of variant
 	 * @return int
 	 *
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 * @throws RestException 401
 	 * @throws RestException 404
 	 *
@@ -1752,7 +1752,7 @@ class Products extends DolibarrApi
 	 * @param  array  $features                 List of attributes pairs id_attribute->id_value. Example: array(id_color=>id_Blue, id_size=>id_small, id_option=>id_val_a, ...)
 	 * @return int
 	 *
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 * @throws RestException 401
 	 * @throws RestException 404
 	 *
@@ -1807,7 +1807,7 @@ class Products extends DolibarrApi
 	 * @param  array $request_data Datas
 	 * @return int
 	 *
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 * @throws RestException 401
 	 *
 	 * @url PUT variants/{id}
@@ -1841,7 +1841,7 @@ class Products extends DolibarrApi
 	 * @param  int $id 	ID of Variant
 	 * @return int		Result of deletion
 	 *
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 * @throws RestException 401
 	 *
 	 * @url DELETE variants/{id}
@@ -1869,7 +1869,7 @@ class Products extends DolibarrApi
 	 * @param  int $selected_warehouse_id ID of warehouse
 	 * @return int
 	 *
-	 * @throws RestException 500
+	 * @throws RestException 500	System error
 	 * @throws RestException 401
 	 * @throws RestException 404
 	 *
diff --git a/htdocs/societe/class/api_thirdparties.class.php b/htdocs/societe/class/api_thirdparties.class.php
index 47e893846e6..962bbf021b8 100644
--- a/htdocs/societe/class/api_thirdparties.class.php
+++ b/htdocs/societe/class/api_thirdparties.class.php
@@ -1409,7 +1409,7 @@ class Thirdparties extends DolibarrApi
 		if ($result > 0) {
 			return array("success" => $result);
 		} else {
-			throw new RestException(500);
+			throw new RestException(500, 'Error generating the document '.$this->error);
 		}
 	}
 
diff --git a/htdocs/ticket/class/api_tickets.class.php b/htdocs/ticket/class/api_tickets.class.php
index 75c2db21224..3151f75877b 100644
--- a/htdocs/ticket/class/api_tickets.class.php
+++ b/htdocs/ticket/class/api_tickets.class.php
@@ -377,7 +377,7 @@ class Tickets extends DolibarrApi
 		}
 		$this->ticket->message = $ticketMessageText;
 		if (!$this->ticket->createTicketMessage(DolibarrApiAccess::$user)) {
-			throw new RestException(500);
+			throw new RestException(500, 'Error when creating ticket');
 		}
 		return $this->ticket->id;
 	}
@@ -438,7 +438,7 @@ class Tickets extends DolibarrApi
 		}
 
 		if (!$this->ticket->delete($id)) {
-			throw new RestException(500);
+			throw new RestException(500, 'Error when deleting ticket');
 		}
 
 		return array(
diff --git a/htdocs/user/class/api_users.class.php b/htdocs/user/class/api_users.class.php
index 68aa2b650f7..66d842c3564 100644
--- a/htdocs/user/class/api_users.class.php
+++ b/htdocs/user/class/api_users.class.php
@@ -466,7 +466,7 @@ class Users extends DolibarrApi
 	 *
 	 * @throws RestException 401 Not allowed
 	 * @throws RestException 404 User not found
-	 * @throws RestException 500 Error
+	 * @throws RestException 500 System error
 	 *
 	 * @url	GET {id}/setGroup/{group}
 	 */