If a previous version worked better try wiping out and reestablishing the firewall rule for it.
Some firewalls restrict applications that have changed in case they were infected by a virus.

Simply updating an existing rule may not work. Norton's firewall had a sneaky bug that
appeared to accept the update but still blocked it. Other firewalls could develop such a
bug too. The only way to be sure is delete the old rule and build a fresh one from scratch.