diff --git a/application/exceptions/CoreTemplateException.php b/application/exceptions/CoreTemplateException.php
new file mode 100644
index 000000000..fb016264f
--- /dev/null
+++ b/application/exceptions/CoreTemplateException.php
@@ -0,0 +1,17 @@
+<?php
+/*
+ * @copyright   Copyright (C) 2010-2021 Combodo SARL
+ * @license     http://opensource.org/licenses/AGPL-3.0
+ */
+
+/**
+ * @since 3.0.0 N°3522
+ */
+class CoreTemplateException extends CoreException
+{
+	public function __construct(Exception $oTwigException, string $sTemplatePath)
+	{
+		$sMessage = "Twig Exception when rendering '$sTemplatePath' : ".$oTwigException->getMessage();
+		parent::__construct($sMessage, null, '', $oTwigException);
+	}
+}
\ No newline at end of file
diff --git a/dictionaries/en.dictionary.itop.ui.php b/dictionaries/en.dictionary.itop.ui.php
index 4ee7a9dcb..536bd9efc 100644
--- a/dictionaries/en.dictionary.itop.ui.php
+++ b/dictionaries/en.dictionary.itop.ui.php
@@ -460,7 +460,6 @@ Dict::Add('EN US', 'English', 'English', array(
 	'UI:Error:MaintenanceMode' => 'Application is currently in maintenance',
 	'UI:Error:MaintenanceTitle' => 'Maintenance',
 	'UI:Error:InvalidToken' => 'Error: the requested operation has already been performed (CSRF token not found)',
-	'UI:Error:TemplateRendering' => 'Cannot render template',
 
 	'UI:GroupBy:Count' => 'Count',
 	'UI:GroupBy:Count+' => 'Number of elements',
diff --git a/dictionaries/fr.dictionary.itop.ui.php b/dictionaries/fr.dictionary.itop.ui.php
index c6d2bd335..6f7be9d14 100644
--- a/dictionaries/fr.dictionary.itop.ui.php
+++ b/dictionaries/fr.dictionary.itop.ui.php
@@ -456,7 +456,6 @@ Dict::Add('FR FR', 'French', 'Français', array(
 	'UI:Error:MaintenanceMode' => 'L\'application est en maintenance',
 	'UI:Error:MaintenanceTitle' => 'Maintenance',
 	'UI:Error:InvalidToken' => 'Erreur: l\'opération a déjà été effectuée (CSRF token not found)',
-	'UI:Error:TemplateRendering' => 'Impossible de rendre le template',
 
 	'UI:GroupBy:Count' => 'Nombre',
 	'UI:GroupBy:Count+' => 'Nombre d\'éléments',
diff --git a/lib/composer/autoload_classmap.php b/lib/composer/autoload_classmap.php
index 7bb74608b..66d18fae1 100644
--- a/lib/composer/autoload_classmap.php
+++ b/lib/composer/autoload_classmap.php
@@ -345,6 +345,7 @@ return array(
     'CoreOqlMultipleResultsForbiddenException' => $baseDir . '/application/exceptions/oql/CoreOqlMultipleResultsForbiddenException.php',
     'CorePortalInvalidActionRuleException' => $baseDir . '/application/exceptions/CorePortalInvalidActionRuleException.php',
     'CoreServices' => $baseDir . '/core/restservices.class.inc.php',
+    'CoreTemplateException' => $baseDir . '/application/exceptions/CoreTemplateException.php',
     'CoreUnexpectedValue' => $baseDir . '/application/exceptions/CoreUnexpectedValue.php',
     'CoreWarning' => $baseDir . '/application/exceptions/CoreWarning.php',
     'CryptEngine' => $baseDir . '/core/simplecrypt.class.inc.php',
diff --git a/lib/composer/autoload_static.php b/lib/composer/autoload_static.php
index 3a9c831ec..bd5d78469 100644
--- a/lib/composer/autoload_static.php
+++ b/lib/composer/autoload_static.php
@@ -575,6 +575,7 @@ class ComposerStaticInit0018331147de7601e7552f7da8e3bb8b
         'CoreOqlMultipleResultsForbiddenException' => __DIR__ . '/../..' . '/application/exceptions/oql/CoreOqlMultipleResultsForbiddenException.php',
         'CorePortalInvalidActionRuleException' => __DIR__ . '/../..' . '/application/exceptions/CorePortalInvalidActionRuleException.php',
         'CoreServices' => __DIR__ . '/../..' . '/core/restservices.class.inc.php',
+        'CoreTemplateException' => __DIR__ . '/../..' . '/application/exceptions/CoreTemplateException.php',
         'CoreUnexpectedValue' => __DIR__ . '/../..' . '/application/exceptions/CoreUnexpectedValue.php',
         'CoreWarning' => __DIR__ . '/../..' . '/application/exceptions/CoreWarning.php',
         'CryptEngine' => __DIR__ . '/../..' . '/core/simplecrypt.class.inc.php',
diff --git a/sources/application/TwigBase/Twig/TwigHelper.php b/sources/application/TwigBase/Twig/TwigHelper.php
index ee7c60c12..6c4478993 100644
--- a/sources/application/TwigBase/Twig/TwigHelper.php
+++ b/sources/application/TwigBase/Twig/TwigHelper.php
@@ -7,9 +7,7 @@
 namespace Combodo\iTop\Application\TwigBase\Twig;
 
 use Combodo\iTop\Application\TwigBase\UI\UIBlockExtension;
-use Combodo\iTop\Application\UI\Base\Component\Alert\AlertUIBlockFactory;
-use Combodo\iTop\Renderer\BlockRenderer;
-use Dict;
+use CoreTemplateException;
 use IssueLog;
 use Twig\Environment;
 use Twig\Error\Error;
@@ -116,53 +114,37 @@ class TwigHelper
 	 * @param bool $bLogMissingFile
 	 *
 	 * @return string
-	 * @throws \Twig\Error\RuntimeError
-	 * @throws \Twig\Error\SyntaxError
-	 * @throws \Exception
+	 * @throws \CoreTemplateException
 	 */
 	public static function RenderTemplate(Environment $oTwig, array $aParams, string $sName, string $sTemplateFileExtension = self::DEFAULT_FILE_TYPE, bool $bLogMissingFile = true): string
 	{
 		try {
 			return $oTwig->render($sName.'.'.$sTemplateFileExtension.'.twig', $aParams);
-		} catch (Error $e) {
-			$sPath = '';
-			if ($e->getSourceContext()) {
-				$sPath = utils::LocalPath($e->getSourceContext()->getPath()).' ('.$e->getLine().') - ';
+		}
+		catch (Error $oTwigException) {
+			$oTwigPreviousException = $oTwigException->getPrevious();
+			if (!is_null(($oTwigPreviousException)) && ($oTwigPreviousException instanceof CoreTemplateException)) {
+				// handles recursive calls : if we're here, an exception was already raised in a child template !
+				throw $oTwigPreviousException;
 			}
-			$sMessage = $sPath.$e->getMessage();
 
-			if (strpos($e->getMessage(), 'Unable to find template') === false) {
-				IssueLog::Error($sMessage);
+			$sPath = '';
+			if ($oTwigException->getSourceContext()) {
+				$sPath = utils::LocalPath($oTwigException->getSourceContext()->getPath()).' ('.$oTwigException->getLine().') - ';
+			}
 
-				return static::GenerateEndUserError(Dict::S('UI:Error:TemplateRendering'), $sMessage);
+			if (strpos($oTwigException->getMessage(), 'Unable to find template') === false) {
+				//TODO handle ajax ??
+				// this will trigger error page, and will log to error.log !
+				throw new CoreTemplateException($oTwigException, $sPath);
 			}
 
 			if ($bLogMissingFile) {
-				IssueLog::Debug($sMessage);
+				$sLogMessageMissingFile = "Twig : missing file '$sPath' : ".$oTwigException->getMessage();
+				IssueLog::Debug($sLogMessageMissingFile);
 			}
 		}
 
 		return '';
 	}
-
-	/**
-	 * @param string $sTitle
-	 * @param string $sMessage
-	 *
-	 * @return string error panel markup
-	 *
-	 * @throws \ReflectionException
-	 * @throws \Twig\Error\LoaderError
-	 * @throws \Twig\Error\RuntimeError
-	 * @throws \Twig\Error\SyntaxError
-	 * @since 3.0.0 N°3522 method creation
-	 */
-	protected static function GenerateEndUserError(string $sTitle, string $sMessage): string
-	{
-		$oAlert = AlertUIBlockFactory::MakeForFailure($sTitle, $sMessage)
-			->SetIsClosable(false)
-			->SetIsCollapsible(false); // not rendering JS so...
-
-		return BlockRenderer::RenderBlockTemplates($oAlert);
-	}
 }