HBO Go is working again. But I'm still no closer to knowing why or how to (quickly) solve it the next time it happens. During the several hours I spent talking to multiple techs and salespeople last night we:
reset my password
reset the UDB data
forwarded ports (but only for Apple TV)
fully activated my account (because I did not have a box hooked up)
was awarded 30 days complimentary HBO to hold us over till we got this solved.
None of these things helped during the 4 hours that followed my calls last night (I still kept getting the "This network is not included in your current Xfinity subscription" error.) But this morning HBO Go is working everywhere again (Apple TV, ipads, laptops, work computer at different locastion).
I'm happy the problem is solved, but since this is the second time I've dealth with this already I fear that this is going to be a fiasco evey month. And while some of the individual techs I've talked to have been courteous and tried their best the overall Comcast customer service system is pretty dismal (compartmentalized, way too much waiting on hold, clueless outsourced CSR's from India who talk in boilerplate, having to re-explain the problem to eveyone you talk to, etc).