[kenfox]

We had a similar problem with Windows Firewall. We keep it enabled, but add exceptions for all the necessary software. Unfortunately Windows doesn't make it obvious (to me at least) whether you are connected in Home, Work or Public zones.

For some reason the firewall rules were inconsistent across the different zones and occasionally we were in Public instead of Work.

Opening up the firewall settings in control panel and checking the boxes across all zones for FRC software fixed the issue.