blocking of PBS Passport

I am new to PBS passport. The xfinity comcast streaming appears to be blocking Passport. The PBS or OPB tech suggests that the router or this XUMO- Xfinity might be blocking doubleclick.net which distributes the mandated sponsor ads with the Passport programs.  I went to our Gateway router, but didn't find any blocked url. What I see is a continuous "circle" as if the program is trying to be downloaded.

The discussion on PBX Passport being lost has only one comment- no discussion.