diff --git a/htdocs/accountancy/class/accountancyexport.class.php b/htdocs/accountancy/class/accountancyexport.class.php
index 472f5b5ce38..3ed4c1c7583 100644
--- a/htdocs/accountancy/class/accountancyexport.class.php
+++ b/htdocs/accountancy/class/accountancyexport.class.php
@@ -181,7 +181,7 @@ class AccountancyExport
 		);
 
 		global $hookmanager;
-		$code = $formatcode[$type];
+		$code = $formatcode[$type] ?? '';
 		$parameters = array('type' => $type);
 		$reshook = $hookmanager->executeHooks('getFormatCode', $parameters, $code);