For Palo Alto Networks Panorama and NSX-T integration, after the registration and service definition has become successful and it has created an entry on NSX-T for that service definition, once the Panorama has been unavailable for any reason, the service definition will get stuck in Out-of-Sync state and any further integration between the PAN and VMware will fail even if try to register with another Panorama.
The cause of the issue is related to the service definition/manager created by partner and should be removed gracefully by partner (Panorama), but it has become unavailable.
The best route would be to recover the Panorama and remove (un-register) gracefully from the Panorama.
For workaround to remove the service definition/manager using API, please contact Broadcom Technical Support for assistance.
See Creating and managing Broadcom support cases for details on opening a case.