Well, odd to me. I use K9, a free Bayesian spam proxy I’ve used for ~20 years. It doesn’t do TLS. So I have:
Outlook <-> K9 <-> stunnel <-> Internet
for email connections.

This morning I wasn’t getting anything on my dozen or so POP connections that go through that (Exchange email was fine). Restarted Outlook (making sure it had really closed), no joy. Then I noticed that while doing a mail check, K9 was throbbing for long periods. There’s not much to do with K9, so next I looked at stunnel, whose log was full of:
2023.01.26 09:39:26 LOG3[18110]: No more addresses to connect

2023.01.26 09:39:36 LOG3[18111]: s_connect: s_poll_wait 146.20.147.244:995: TIMEOUTconnect exceeded

Reloaded stunnel config and all is well.

So, not a big deal, but…any guesses what was going on here? stunnel 5.57, Windows 10.