Darkpenguin66-
You were viewing a thread titled "Can't uninstall HBO Max app" but then entered a separate message without changing the title.
From your text you CAN and have uninstalled the HBO Max channel app, so that makes things a bit confusing when the post title and post text say different things.
The HBO Max subscription you obtained from internet provider should NOT be listed in your subscriptions shown on your Roku account. Only subscriptions obtained THROUGH ROKU are listed there.
As you've indicated, HBO seems to be having current problems with the Roku version of their app they have supplied to Roku. The remove / restart / resinstall process (do all three in that order) suggested by Anonymous should assure you have a clean copy of the latest version of the channel app, but if the app itself is where the problem lies you don't have a cure yet.