To resolve the connection issue after migrating to a QNAP Docker container, you must manually transfer your license. The Docker container generates a new ID, which the Roon system treats as a completely new installation.
Perform the following steps:
Restart your Roon Server container in QNAP Container Station.
Open your Roon Remote app. On the startup screen, click the Select a different Roon Server button.
Select the new Roon Server instance that appears in the list.
Log in with your Roon account credentials.
You will be prompted to unauthorize the previous native QNAP installation. Confirm this action to release the license to your new Docker container.
Provide an update on your connection status after completing these steps.