The problem is not in front office but in back office. As i said, in back office when we want to modify an event and save it we have an error message :
An error occurred while saving your page. Various issues can cause the backup to fail, such as lack of server resources, firewall blockages, plugin conflicts, or server misconfiguration. You can try backing up again by clicking Try Again, or you can download a backup of your unsaved page by clicking Download Backup. Backups can be restored using the portability system the next time you edit your page.
The plugin conflict is with Complianz
