Why can't I join my own session on my tablet or mobile device?
Have you started a session in the HoloLens 2 and then tried to join that session on your tablet or mobile device only to not be able to gain access?
Once you have launched a session using your credentials, you can no longer use that login information, the system will not allow this. In order to join the session you started, you will need to use a different set of credentials on the mobile device or tablet.