As of a few minutes ago old.reddit.com now seems to requre logging in to access it.
Shame as it was still the best place to browse for info about some niche interests.
Edit: Seems like they might be testing the change as it is hit or miss at the moment.
Edit: Adding this to My flilters in uBlock Origin seems to fix the issue for the time being:
||reddit.com^$header=referer:
It hasn’t worked for me for a couple weeks now. I only lurk there when I am checking to see if a tech question I have has already been answered by someone, so it’s not a huge loss for me. It also stopped working on some subreddits before others. From the same computer at the same time I could see /r/Delta but could not see /r/MLS on old.reddit.