HBO Go Activate

Since April 2018 I cannot activate HBO GO.  It says I do not have a valid HBO subscription.  Which I do.  This is NOT an HBO issue as I also cannot activate Showtime or Starz.  I get the same mesage from all 3 that I do not have a subscription.  I have wasted hours upon hours of time on the phone with AT&T and researching the internet for an answer.  Obviously this has been a problem since atleast 2014.   Will someone please address this issue and fix before I get totally fed up and switch service.

Thank you