Any time the login process does not allow a user to progress to the portal of choice the interface should explain the reason to the user so they can relay that to their admin. For example, if the HME user does not have an active code set or there are missing markets or products etc. Sometimes there are other issues that cause a login loop. It would be a better experience for the user of there was more feedback on the issues rather than frustrating the user with a vague repeat loop that induces a support call.
Idea created on behalf of Tim Arrowsmith