diff --git a/library/Icingadb/Hook/CustomVarRendererHook.php b/library/Icingadb/Hook/CustomVarRendererHook.php
index 8dca61dca..bdd62e185 100644
--- a/library/Icingadb/Hook/CustomVarRendererHook.php
+++ b/library/Icingadb/Hook/CustomVarRendererHook.php
@@ -69,7 +69,8 @@ final public static function prepareForObject(Model $object): Closure
                     $hooks[] = $hook;
                 }
             } catch (Throwable $e) {
-                Logger::error('Failed to load hook %s:', get_class($hook), $e);
+                Logger::error('Failed to load hook %s: %s', get_class($hook), $e);
+                Logger::debug($e);
             }
         }
 
@@ -85,7 +86,8 @@ final public static function prepareForObject(Model $object): Closure
                     $renderedValue = $hook->renderCustomVarValue($key, $value);
                     $group = $hook->identifyCustomVarGroup($key);
                 } catch (Throwable $e) {
-                    Logger::error('Failed to use hook %s:', get_class($hook), $e);
+                    Logger::error('Failed to use hook %s: %s', get_class($hook), $e);
+                    Logger::debug($e);
                     continue;
                 }