First, this is not about my home network, but I could not find a board dedicated to posting about problems with xfinitywifi hotspots.
I'm on vacation in Ocean City MD, and there are plenty of xfinitywifi hotspots around. We have 4 devices: iPhone 6S plus, iPad air, WIndows 10 laptop, and a Samsung Galaxy S5 phone. On our first day here, all of our devices were able to use the hotspots just fine. After about 24 hours, all of our devices started having problems. They connect to the hotspots, but then indicate no internet access. I cannot figure out what is wrong. It doesn't matter where we are in town, we get the same behavior. I've checked our devices, but cannot find any problems on them. In fact, it would seem odd for all 4 devices to suddenly start having the same problem at the same time.
so far, I've tried:
1) rebooting the devices
2) Forgetting the xfinitywifi network
3) going to another xfinitywifi hotspot (2 miles apart)
Same here in Atlanta, Georgia. We can connect to the xfinity wifi as if it's still presented as a locatable hotspot. It will connect to the router or access point but no internet works at all. I have tried the same as you rebooting my settings, network adapter, etc. No luck at all. It started happening here yesterday.