ErrorException Trying to access array offset on value of type null [closed]

Answer 1

Your problem was caused by a change to the php new version. If you do not know which page caused this error, you can use the Symfony test. Maybe this link will help you:

https://symfony.com/doc/current/contributing/code/tests.html

Answer 2

The PHP Version is indeed the problem. On the previous host it was PHP 7.3 but the new one run 7.4 so it caused the problem.

Now I have downgraded to PHP 7.3.1 and the application now works fine.

Thanks so much.