Thanks for reaching out to the Roku Community. We'd like to investigate and try to help.
After reading your note, it seems like you are unable to add a channel and encountering an error of "no linked device" in your Roku player, is that correct?
As a first step, could you try to check if you go into the account settings of your Roku device through Settings > System > About, are you using the same email that is shown?
Please be noted when you add a channel to your Roku device, you are actually adding it to your Roku account. As a result, the channel will automatically be added to all Roku devices linked to your Roku account. When you remove a channel, the same is true. It will be removed from all Roku devices linked to your Roku account.
For full information on this, you can take a look at this link: How do I add channels to my Roku® streaming device? | Official Roku Support
Please keep us posted If you continue encountering errors in adding channels.