https://www.jevents.net/discussions/new-issue-after-installation is the same issue, please Geraint response in this post.
in the post "new Issue after installation" i reported the debuging errors.
that are:
Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 516096 bytes) in /home/aragonar/public_html/portal/libraries/joomla/database/driver/mysqli.php on line 894
this is the error, that happens when i add an event in the calendar. the site goes down.
And when i delete or disable the event in the backend of jevents it shows this error
-> Notice: Undefined variable: linkprevious in /home/aragonar/public_html/portal/modules/mod_jevents_cal/tmpl/ext/calendar.php on line 188
The site still working after deleted but if i try to add an event it crashes again.