Hello,

I will move your topic to the correct category of the forum, as "Miscellaneous" category is for not-related-to-iCagenda topic (so i don't check it often... this forum category is for people who want to speak about different and miscellaneous subject.)

About your issue, this is due to another extension( i think it's a plugin, as issue in admin as well as site side).
Note: this could be the editor, and/or a button editor plugin

So no error code, only (but not always easy to find) a script issue in one extension

Maybe i could check if you have an online link to the submit form ?

Best Regards,
Cyril