Messages are not showing body or other message titles in thread

I have no idea what I've done wrong but when I click to read individual posts, the body is not appearing. And the message title tree is not displaying for people to click to read other posts in the thread.

Is this something that could be due to being on PHP 7? I've again tried PHP 7.3 and 7.0 but that had no impact on this problem.

I'm also noticing that there are major caching issues causing problems with the functionality. I will change a setting in the admin area, but then when I go back to the settings page, it is showing the setting how I previously had it. Then I hit CTRL-F5 and the setting then shows as correct.

I noticed another problem that when I use a non-admin user account to post, it says it must be approved by an admin even though I have that setting disabled by default.

I had this same site working perfectly several years ago. I am trying to bring it back now. I uploaded all the files, imported the MySQL database, then performed Phorum software and module updates as needed. Everything looks like it should, but a lot of functionality is breaking. I can't figure out why, except for the PHP version being something major that is different now.

Any assistance would be appreciated.

I figured out why the body of the messages wasn't displaying. I disabled the Mailhide module and that problem stopped.

Still having the problems with caching.

I also found another error when I tested the Report a post feature. Lines 65 and 69 of the report.php file had to be edited. They previously had:

"body" => wordwrap($message["body"], 72),
"explanation" => wordwrap($_POST["explanation"], 72),

and I changed them to:

"body" => wordwrap($message["body"], 72, "\n", TRUE),
"explanation" => wordwrap($_POST["explanation"], 72, "\n", TRUE),

That solved the fatal error I was getting.