HBO Go subscription to HBO Max problem

I previously had an HBO Go subscription, but when the apps were eventually migrated to HBO Max, I couldn't restore purchases with the same subscription. The issue came when I went to the HBO Max app and tried to restore the purchase but the error showed that I was "unable to restore purchase, your subscription is not active"

I don't understand, because my HBO Go subscription is still active. I tried reaching out to HBO Max's customer support, but they weren't very helpful.

If you’ve encountered the same issue as I have, seeking your assistance in helping me find the best solution to resolve this.

Thank you in advance.