After update with PHP 8.0

[HebRech GmbH & Co. KG]

After updating the Php version, a page is not displayed anymore and I receive the error message you find in the attached image. As you can see the error comes from a system file not from an external code.
I need your help please.

[Marc]

This will be from 3rd party plugins most likely. Try recovery mode, which you can read more about here

https://invisioncommunity.com/4guides/welcome/getting-support-r292/

Also check any custom pages templates, as these could also be causing an issue (and likely are, looking at the error)