Some of the essential modbots for our 4 million subscriber subs use web browser (using selenium) for a decade , from a data center IP.

Reddit changed ~ a year ago to display

You've been blocked by network security.

To continue, log in to your Reddit account or use your developer token

and that's fine, we/they'd just log in and perform essential help.

Starting 24 hours ago, entering valid username/password from multiple different data centers results in

"invalid username or password"

Copy pasting the same username/password from my clipboard on my home IP works.

I tried with multiple accounts. (it isn't account specific)

Update: this was happening in two data centers (one mid-west, one east coast) a few hours ago. Now it works again in one of them. They are probably being routed to different reddit servers based on their location - the east coast server now works, the midwest server still gives the bogus "invalid username or password" message.

I also requested that one of these servers have their IP whitelisted (based on the message "If you think you've been blocked by mistake, file a ticket below and we'll look into it."). I did that April 25th but haven't heard back yet.

EDIT - hour later - RESOLVED

Now valid accounts/passwords work on both servers, so if it was a server side bug fix it has propagated to both regions. I'll probably delete this after a few days if there are no regressions and/or this isn't helpful for anyone else.