I’ve not seen any errors as such, that I recognise.
The steps that led to the problem:
Webmin (Perl-Based GUI I use to manage my VPS) told me I had 50+ package updates, all standard routine stuff, that I apply frequently, and to my main server as well.
After restart the VPS, I went to my forums, no-go. I went to the admin panel, noticed two upgrades, one for docker and one for discourse, ran them both, still, nothing.
Mobile forums work fine, web-based don’t.
I’m obviously missing something, but what the heck it is I don’t know