White page when updating or creating a new course

Hi everybody I have an error when updating or creating a new course on my opigno... Can't find the issue... I have just create 3 new fields for the course node to display on the course page and the certificate. Everything was working fine and suddenly, when I go to the course page again, I get a white page... I can still access the course that have not been updated... I have enabled maintenance mode and displaying error message on the platform and I got this : When I edit a course and go back to the course administration list --> Warning : array_keys() expects parameter 1 to be array, null given dans EntityReference_SelectionHandler_Views->validateReferencableEntities() (ligne 141 dans xx\xx\profiles\opigno_lms\modules\contrib\entityreference\plugins\selection\EntityReference_SelectionHandler_Views.class.php). Warning : array_flip() expects parameter 1 to be array, null given dans entityreference_field_validate() (ligne 223 dans xx\xx\profiles\opigno_lms\modules\contrib\entityreference\entityreference.module). Warning : array_diff_key(): Argument #2 is not an array dans entityreference_field_validate() (ligne 223 dans xx\xx\profiles\opigno_lms\modules\contrib\entityreference\entityreference.module). Notice : Undefined index: drupal dans update_requirements() (ligne 35 dans xx\xx\modules\update\update.install). On the white page of the updated course --> Additional uncaught exception thrown while handling exception. Original PDOException: in locale() (line 749 of xx\xx\modules\locale\locale.module). Additional PDOException: in dblog_watchdog() (line 160 of xx\xx\modules\dblog\dblog.module). Hope you could help me ! Many Thanks