"old" now serves "no healthy upstream" from here

Still works here. Not that it matters much, but handy for viewing the odd search result.

old.reddit.com allowed viewing reddit in the old format. As of today, it seems, this address gives the error: "no healthy upstream".

although i just clicked it, and it worked fine...so maybe it was temporary.

I think they’re saying they’re getting that error message when they browse Reddit using https://old.reddit.com/

I was getting the same. Seems to have cleared up. If you search this, you'll see it has happened before. It's a server error.

Loads fine for me