HBO Max Subscription Expired (another one)

Hello. Several months ago I cancelled an AT&T wireless service (Unlimited Home Phone and Internet) that I originally used to get HBO Max.  I still have the Unlimited Elite Wireless plan for mobile phone service, and should still be eligible for HBO Max.

Ever since the original service was cancelled I have been unable to access HBO Max though. HBO says my subscription has expired.  

I have tried the troubleshooting steps found on this forum...

- Signed out of all devices from the website. I waited many days and tried signing in with AT&T as the provider, and still get the subscription expired message. I cleared cookies and cache and every combination of options to try to login differently.

- I tried signing up for a new HBO account with the same email I originally used, but that was a dead end.

I don't have the "activate HBO Max" button on the AT&T website either.

For some reason I have 2 AT&T accounts (maybe because I had DirectTV many years ago). The username fore the account with my wireless service is a regular username (not email), and the old account username is my email address.   This is the same email address my HBO Max account uses. That might possibly be the problem. When I try to sign in to HBO Max with AT&T as the provider, I do use the correct wireless account login.