This is very frustrating.
I have been accessing servername.local on Firefox. That's its URL. No www.
At some time, servername.local ceased to be available and I got an error message: "Server not found". Fair enough.
However, Firefox didn't just try servername.local, it tried www.servername.local as well. "Server not found" again.
The problem is, now that servername.local is back up and running (I can get to it with other browsers and by IP address), Firefox always tries for www.servername.local, no matter if I type in the correct non-WWW URL or use a bookmark.
I cleared the cache, I cleared the history. No change. I flushed the DNS cache, that didn't help either.