Aborting! Domain is not configured!

I think you mean the Discourse rebuild. That definitely didn’t abort, and the forum still works.

Looking properly at the text, it looks like a line of Ruby at the command line which checks whether DISCOURSE_HOSTNAME is still “discourse.example.com” and would abort the rebuild if it were. The next line is similar. So, as you say, nothing to worry about.

Rightly or wrongly, I started four topics tonight. I think you mean this one: ERROR: Can't find Ruby library file or shared library pups, as it was the earliest one. What’s the connection? Thanks.