Move Joomla from Test to working > error

Hi,
i tried to move my Joomla4 Install with full function of JEM from a Test environment to working Site ( ).
Backup database and files (with easyjoomlabackup from ) transfer to new domain, extract and adapt.
It runs' yesterday really fine !!... today i'm getting an error "unsupported operand" (see screenshot) when i click on menu "Veranstaltungen - aktuelle Veranstaltungen )
Tryed php from 7.3 to "URL-Rewrite"... no Chance

Help please!
Markus.

sorry, I don't know easyjoomlabackup. I work always with the free akeeba backup and have nearly never problems.
Can you put debug mode= on and error notices=maximum. Then you get more infos about the error.
Jojo
But do you really use php 7.3? it's far in the past!

Hi,
i think it is not a backup Problem, but a PHP
Yesterday evening it work,
today morning not !!

Thanks!

DEBUG in Joomla:

2023-12-21T18:12:52+00:00 CRITICAL 84.166.150.121 error Uncaught Throwable of type TypeError thrown with message "Unsupported operand types: string + int". Stack trace: #0 [ROOT]/components/com_jem/(43): JemHelper::cleanup()
#1 [ROOT]/libraries/src/Dispatcher/(71): require_once('/home/')
#2 [ROOT]/libraries/src/Dispatcher/(73): Joomla\CMS\Dispatcher\LegacyComponentDispatcher::Joomla\CMS\Dispatcher\{closure}()
#3 [ROOT]/libraries/src/Component/(361): Joomla\CMS\Dispatcher\LegacyComponentDispatcher->dispatch()
#4 [ROOT]/libraries/src/Application/(208): Joomla\CMS\Component\ComponentHelper::renderComponent()
#5 [ROOT]/libraries/src/Application/(249): Joomla\CMS\Application\SiteApplication->dispatch()
#6 [ROOT]/libraries/src/Application/(293): Joomla\CMS\Application\SiteApplication->doExecute()
#7 [ROOT]/includes/(61): Joomla\CMS\Application\CMSApplication->execute()
#8 [ROOT]/(32): require_once('/home/')
#9 {main}