#127: Mail.app stuck at fetching mail for gmail accounts on 10.10.3

Solved!
After upgrading to OS X 10.10.3, Mail.app is stuck at "Fetching Mail..." for all Gmail POP3 accounts. Connection doctor logs report: READ Feb 27 09:54:23.788 [kCFStreamSocketSecurityLevelTLSv1_0] -- host:pop.gmail.com -- port:995 -- socket:0x6180002b0f20...