I thought it was Comcast, because we also have Comcast business at work, and last week I couldn't access the forum at all from my work PC.
At Home it seems to always connect when I first visit, then become unavailable after clicking a few links. It then would usually not work for 30-60 minutes, then start working again.
For me, it happens here, and to a lesser extent, the UCCNC forum. No other sites are affected.
And yes, it always worked on my phone (Verizon via XFinity Mobile).
But this week it's working fine.