PR_END_OF_FILE_ERROR on 2 of my 3 WordPress sites but only from my MacBook Pro
I would use the developer console in your browsers to start to look at the web site errors. That almost always shows you the error in these cases, however if there are lots of errors, you may spend some time eliminating them one by one.
Here are step by step directions to get the console on Safari. There are some amazing tutorials on FireFox and I know a lot of people prefer that for this exercise so maybe someone has that experience to share here as an edit or another answer.

https://support.apple.com/guide/safari/use-the-developer-tools-in-the-develop-menu-sfri20948/mac
https://support.apple.com/guide/safari-developer/welcome/mac

The benefit of these tools is you will have actionable items to take to vendors or ask wordpress experts how that error works and which precise URL triggered it. Most Wordpress pages have about 100 to 300 elements on “one page” so the vast majority of things can work and you still see an error thrown.