My server are not sending emails about notifications

i just installed my nextcloud admin notifications, but, when i post something in the notifications, my users does not receive emails.
i did setup the smtp server properly but it still does not work…
i am using the latest nextcloud with php 7.4 and in a shared hosting, and cron are set to run each minute.

if i go to settings > activities, the send activities notification email is unchecked, if i try to check it, it does check, but if i reload, baaaamnnn, the option get unticked again.
help me cause i do really need to send admin notifications via email
and yes, all options in the activities tab are checked, but, the activate via email in the beggining of the page are not checked…
if i check, it gets unchecked when i leave the page…
what to do… is there any sql table to look in to force the email activities… i need to send emails for each admin notifications!
thanks