Problem when moving site to another hoster

I moved the site from a customer to another hosting (PHP 7.4.14) and all is working fine EXPECT of the homepage. I have tried now so much but not sure where the problem is. Anybody a tip?

Array to string conversion

Again, all other pages are working, it’s only the homepage. Maybe it’s a problem with .htaccess?

All right, I found the bug. It was a problem with the colorpicker plugin from Sylvain which has output a empty value. But does anybody knows why this happens not on my host but on another?

It probably depends on your PHP error level settings in php.ini.