[SOLVED] New Events Impossible

Creation of new events impossible.
Event Save doesn't work
What is the problem ?

My version of Joomla is 3.10.8

Thank you for your issue. Please give more information about your version incl. templates, framework and additional plugins. (with my 3.10.8 and t4_bs5_blank 1.1.2 template it works, (but with t4_bs5_blank 1.1.3+ there's a problem but with joomla content too)

I used by default holygon template created from TemplateCreator ( JOOMLACK)
The version of Joomla is 3.10.8

When in EVENTS, I click on the "New" button, a new windows open. But, even after filled the fields, only the "Cancel" button works.
Click on "Save and New" or "Save and Close" button has no effect.

which jem? which php?

The problem is resolved.
Files named moo*.* in media/system/js directory had been deleted to resolve a GTRANSLATE problem.
These files are restored and JEM is OK now.