ssl protocol error

I'm trying to reach a couple of sites in the directly.com domain. One is app.directly.com. When I'm on my at-home Xfinity WiFi network, I receive ERR_SSL_PROTOCOL_ERROR from Chrome and also on my tablet. When I use my phone's cell service, I can get right through so clearly it's an Xfinity problem. I rebooted the router and it worked for about ten minutes and then failed again. I haven't run into problems with other web sites, just directly.com and only when on the Xfinity WiFi network.