Possible that the Agent stuck or being blocked on the network or security tools that did not get update to the portal with it's latest status.
Also, it could be caused by old agent version, and auto-upgrade is not happening for some reason.
1) Select the device reset the registration status = false
2) Restart the device and monitor the status of the registration. ( take note that the communication of the agent to the backend is taking place up to 4 hours)
3) If the status remains false, try to restart the agent and monitor the log
4) The log located on the path of the device"C:\Program Files (x86)\Quest\On Demand Migration Active Directory Agent\Files" Look for the latest file name agent_<xxxx>.log
and you should see a log entry that shows the device is registered. successfully.
5) If it does not happen, then the next to try is to uninstall and clean up the device including the registry key where the next available support will assist you further after you confirm the above steps 1 to 4 are taking place. Refer to the below KB
https://support.quest.com/kb/4292807/odmad-how-to-remove-a-device-from-odm
6) Download the latest device agent version and uninstall/install the latest one