The answer was resetting my Xfinity router, again.

@XfinityThomasA​ I am on my third day of no Xfinity streaming through ROKU. I have performed all the steps, several times on 3 separate units to no avail. I can get past the 00287 code, and the channel and show title appear in the upper left hand cor

Having same issue. Accomplished all the steps, but will not stream. Any channel chosen shows the show title in the upper left hand corner, as well as the station symbol (such as the peacock feathers and NBC) in the center, but only the 3 flashing dot