Hi,
I just tested the version 3.26 of Creativity on my test website with PHP 8.0.
I got an error.
To be sure that the problem is related to the template, I switched the site template to protostart. Then I disabled Creativity in the extension manager. My website is running.
So I guess, the problem is related to the template.
You can check the problem with the following URL: https://migration.guillenphoto.com/
I can give you access to the admin of my test website if you want. For me it will be helpful.
Let me know what to do.
regards
Amar Guillen