Fatal Error Message on Activello

I wonder if you could help.
I got a fatal error message on Wordpress. How do I fix it? My website address is: https://somebodyfeedseb.com/. Please see screenshot below:

Hey there

What is the version of the PHP on your hosting? make sure it’s not the latest version

It is on PHP 7.3.27. I’ve just tried changing it to PHP 7.2.34, and the error message is still there. Also, when I last updated Activello, my feature photo size on the main page changed and are no longer full width.

Do you have any ideas on how I could sort the error and the width of the pictures?

Error details below:

WordPress version 5.6
Current theme: Activello (version 1.4.3)
Current plugin: (version )
PHP version 7.3.27

Hi @ievagreber

strange, I was not able to replicate that problem on my side, could you please send me your admin details privatelly here?