I'm encountering similar behaviour in the daemon since booting this computer up tonight too,  I hadn't encountered this issue before and I'm unsure that it's a firewall problem in my case.  I'm planning on saving my wallets and reinstalling the software.   Jusf for a check I loaded the Aeon daemon (another cryptonote-based one) and that synced properly. (It's sort of annoying because I wanted to open up one of the wallets   .)