I pay for HBO Max through Amazon prime but when I tried to sign in on my Roku account, it does not recognize it. I don’t have this problem with other TVs in my house. I use Firestick on my other TVs. Anyone have any ideas?
That’s a common problem if you use a third-party like Amazon to pay for content – it often only works only on devices made by that third-party. If you want to watch content on a variety of platforms, it is better to subscribe directly with each content company, and then sign-in on your various devices. (ie: don’t use Amazon, or Roku, or Apple etc. as a payment system.)
Your Max account is with Amazon, so that's why you can access it on Amazon Firestick devices. On Roku you may be able to access via the Amazon Prime app instead of the stand-alone Max app.