Roku HBo subscription help

Hi, last month I did a subscription to HBO Max via Roku. The sub is through Roku not HBO. I think this means I can only watch HBO on Roku devices. I have it on my bedroom roku, but want to put it on my living room Roku as well. But the login I thought I made doesnt work. HBO also says they do not have any account with my email I put in. Is there a way to find out what my log in info is? Roku says my HBO account is active still, I just can not log into any other HBO app on other Rokus. Is there a Roku login trick that I have to do?