VPN doesn't connect when using Xfinity wifi

I use VPN to work. Until last Friday it was working fine but suddenly it stopped working. If I use other internet provider services it works just fine but with Xfinity wifi it will simply connect and disconnect right away. I've had an Xfinity thecnician checking the router and connections in the house and nothing abnormal was found. I've checked Windows Firewall settings and no issues were found. I've talked to my VPN people and they say there's nothing wrong on their side and more than likely the issue is with internet provider. I don't know what to do. Please help!