Thanks Robert! This seems to have narrowed the problem down. On deactivating oEmbed, the problem thread loaded without issue. However I couldn't leave...

Team, I've had no response from support for a while with regards to this issue and am naturally a bit concerned. As explained in my previous post, wpf...

Indeed it has been. I got in touch with my service providers who notified me that the issue was with the wpforo-embeds plugin I have installed; they'v...

Yeah I had a couple of PHP warnings pop up in relation to a single plugin. Deactivated that to no avail; seems like I will have to indeed contact my p...

Okay. And once debugging has been activated, all I need to do is attempt to access the thread URL again? The 504 Gateway error still crops up although...

Thanks Massimo. The sit's live though; believe WP Debug has to be done locally? Not very tech-savvy so I'd appreciate you holding my hand. Thanks.

Thanks for the quick response. I've had WP Super Cache and WP Smush as the only 'Optimizer' plugins that I seem to be using. No other URL redirection ...

Worked. Much thanks for your help. 🙂

Don't have bbPress installed. Is there any way I can delete the 404 posts from the back-end at the very least?

Any suggestions on determining if it really is a CSS issue?

Thanks for getting back. The issue has since gone away for now as the user has decided to redo/delete his original post. Another user attempted to do ...

Understood, thanks for getting back!