diff --git a/htdocs/comm/propal/class/api_proposals.class.php b/htdocs/comm/propal/class/api_proposals.class.php
index 97ea07bf7e6..36a5c9a780d 100644
--- a/htdocs/comm/propal/class/api_proposals.class.php
+++ b/htdocs/comm/propal/class/api_proposals.class.php
@@ -493,7 +493,7 @@ class Proposals extends DolibarrApi
 
 		$result = $this->propal->valid(DolibarrApiAccess::$user, $notrigger);
 		if ($result == 0) {
-			throw new RestException(500, 'Error nothing done. May be object is already validated');
+			throw new RestException(304, 'Error nothing done. May be object is already validated');
 		}
 		if ($result < 0) {
 			throw new RestException(500, 'Error when validating Commercial Proposal: '.$this->propal->error);
@@ -535,7 +535,7 @@ class Proposals extends DolibarrApi
 
 		$result = $this->propal->cloture(DolibarrApiAccess::$user, $status, $note_private, $notrigger);
 		if ($result == 0) {
-			throw new RestException(500, 'Error nothing done. May be object is already closed');
+			throw new RestException(304, 'Error nothing done. May be object is already closed');
 		}
 		if ($result < 0) {
 			throw new RestException(500, 'Error when closing Commercial Proposal: '.$this->propal->error);
diff --git a/htdocs/commande/class/api_orders.class.php b/htdocs/commande/class/api_orders.class.php
index 64958b01ef6..8bfed9d4eb4 100644
--- a/htdocs/commande/class/api_orders.class.php
+++ b/htdocs/commande/class/api_orders.class.php
@@ -537,7 +537,7 @@ class Orders extends DolibarrApi
 
     	$result = $this->commande->cloture(DolibarrApiAccess::$user, $notrigger);
     	if ($result == 0) {
-    		throw new RestException(500, 'Error nothing done. May be object is already closed');
+    		throw new RestException(304, 'Error nothing done. May be object is already closed');
     	}
     	if ($result < 0) {
     		throw new RestException(500, 'Error when closing Order: '.$this->commande->error);
diff --git a/htdocs/contrat/class/api_contracts.class.php b/htdocs/contrat/class/api_contracts.class.php
index 0bc02458869..45595712b68 100644
--- a/htdocs/contrat/class/api_contracts.class.php
+++ b/htdocs/contrat/class/api_contracts.class.php
@@ -479,7 +479,7 @@ class Contracts extends DolibarrApi
 
 		$result = $this->contract->validate(DolibarrApiAccess::$user, '', $notrigger);
 		if ($result == 0) {
-		    throw new RestException(500, 'Error nothing done. May be object is already validated');
+		    throw new RestException(304, 'Error nothing done. May be object is already validated');
 		}
 		if ($result < 0) {
 		    throw new RestException(500, 'Error when validating Contract: '.$this->contract->error);
@@ -525,7 +525,7 @@ class Contracts extends DolibarrApi
 
     	$result = $this->contract->closeAll(DolibarrApiAccess::$user, $notrigger);
     	if ($result == 0) {
-    		throw new RestException(500, 'Error nothing done. May be object is already close');
+    		throw new RestException(304, 'Error nothing done. May be object is already close');
     	}
     	if ($result < 0) {
     		throw new RestException(500, 'Error when closing Contract: '.$this->contract->error);
diff --git a/htdocs/fourn/class/api_supplier_invoices.class.php b/htdocs/fourn/class/api_supplier_invoices.class.php
index 1d7efb236a2..e60fdccd4ad 100644
--- a/htdocs/fourn/class/api_supplier_invoices.class.php
+++ b/htdocs/fourn/class/api_supplier_invoices.class.php
@@ -312,7 +312,7 @@ class SupplierInvoices extends DolibarrApi
 
     	$result = $this->invoice->validate(DolibarrApiAccess::$user, '', $idwarehouse, $notrigger);
     	if ($result == 0) {
-    		throw new RestException(500, 'Error nothing done. May be object is already validated');
+    		throw new RestException(304, 'Error nothing done. May be object is already validated');
     	}
     	if ($result < 0) {
     		throw new RestException(500, 'Error when validating Invoice: '.$this->invoice->error);
diff --git a/htdocs/fourn/class/api_supplier_orders.class.php b/htdocs/fourn/class/api_supplier_orders.class.php
index 22cd4eb191c..74b5bbe43b3 100644
--- a/htdocs/fourn/class/api_supplier_orders.class.php
+++ b/htdocs/fourn/class/api_supplier_orders.class.php
@@ -316,7 +316,7 @@ class SupplierOrders extends DolibarrApi
 
     	$result = $this->order->valid(DolibarrApiAccess::$user, $idwarehouse, $notrigger);
     	if ($result == 0) {
-    		throw new RestException(500, 'Error nothing done. May be object is already validated');
+    		throw new RestException(304, 'Error nothing done. May be object is already validated');
     	}
     	if ($result < 0) {
     		throw new RestException(500, 'Error when validating Order: '.$this->order->error);
diff --git a/htdocs/projet/class/api_projects.class.php b/htdocs/projet/class/api_projects.class.php
index 6fcdfde7ca2..f6364eb0544 100644
--- a/htdocs/projet/class/api_projects.class.php
+++ b/htdocs/projet/class/api_projects.class.php
@@ -513,7 +513,7 @@ class Projects extends DolibarrApi
 
 		$result = $this->project->setValid(DolibarrApiAccess::$user, $notrigger);
 		if ($result == 0) {
-		    throw new RestException(500, 'Error nothing done. May be object is already validated');
+		    throw new RestException(304, 'Error nothing done. May be object is already validated');
 		}
 		if ($result < 0) {
 		    throw new RestException(500, 'Error when validating Project: '.$this->project->error);
diff --git a/htdocs/projet/class/api_tasks.class.php b/htdocs/projet/class/api_tasks.class.php
index f00a536df87..fc006706d81 100644
--- a/htdocs/projet/class/api_tasks.class.php
+++ b/htdocs/projet/class/api_tasks.class.php
@@ -529,7 +529,7 @@ class Tasks extends DolibarrApi
 
         $result = $this->task->addTimeSpent(DolibarrApiAccess::$user, 0);
         if ($result == 0) {
-            throw new RestException(500, 'Error nothing done. May be object is already validated');
+            throw new RestException(304, 'Error nothing done. May be object is already validated');
         }
         if ($result < 0) {
             throw new RestException(500, 'Error when adding time: '.$this->task->error);