Mac Mail stopped downloading messages from Google POP account

Yesterday afternoon Mac Mail stopped downloading messages from Google POP account. The messages are still downloading fine to my iPhone, therefore I don't think it is a Google problem. When I hit the get mail button, it simply gives the "no new mail" sound.

I use a late 2013 Macbook Pro running Mavericks 10.9.3 (have been hesitant to upgrade to Yosemite for fear of various problems). Four other IMAP accounts work fine in Mail. I have tried the usual fixes: restarting Mail, restarting the computer, going offline and online again, etc. Connection Doctor says everything is fine and dandy.

Any ideas anyone? (Would be great if i wouldn't have to spend another half day of work troubleshooting this or re-installing the mail account 🙂)