I think I got my Jetpack from X Theme. Jetpack says to go back to the supplier with problems. Here I am.
Hi I have the same problem. Yesterday I upgraded to WP 5.8.1 from 5.8. Whenever I tried to access posts or pages I got the 500 Internal Server Error. I tried first with changing .htaccess. My PHP Memory was set at 128M and seemed not the problem. Checking my plug ins Jetpack was the problem. I even deactivated all my plug-ins again and only left jetpack active. The problem is jetpack!
I had a similar issue previously with my Siteground (host) plug-in but I could de-activate each issue separately but I can’t seem to do this with jetpack.
When I go into jetpack settings and try to change anything. All I get is an error box ‘Error Updating Setting Api404 Error’ and it won’t allow me. Not very helpful.
I tried the Jetpack Debug and following their trouble shooting but to no avail
Do I have to leave Jetpack off permanently?
I don’t even know what jetpack does for me any more! I know I had got free plug-ins from them in the past