As of last week, Google is on-track to discontinue POP-polling functionality. I've been using this for about 20 years, not sure what to do. What a pain.
Gmail will no longer support checking emails from third-party accounts via POP (support.google.com) https://news.ycombinator.com/item?id=45439670 - 6 days ago, 372 comments
This is alarming if you just skim the headline (which I did, and was slightly alarmed), but it is about having gmail download from third-party accounts, not downloading emails from gmail. I don't think many people do this anyway, but I'm sure it was very convenient for some.