Chandranshu - In testing with a Poly VVX 500, here are the steps I've followed, and the results.
1) Factory Reset the device
2) Installed the supported firmware version 5.9.6.2327
3) Enabled Web Interface
4) Set the provisioning server "http://noam.ipp.sdg.teams.microsoft.com"
5) Device auto restarts, boots, and states "Contacting Provisioning Server"
6) Then "Provisioning Successful"
7) Device shows the Teams Logo and "Sign In to make an emergency call"
😎 Then displays "Line Unregistered"
Line1:.[SIP] (Not Registered)
*SIP:Server-1:obsbc-usea.sdg.teams.microsoft.com (Not Registered 0)
9) Selecting "Sign In" displays "An error occurred. Please try again later"
What I’ve found, is if I leave the device powered on and in this "Unregistered" state , it will eventually register successfully, but typically takes 8-10 hours to do so. A subsequent reboot produces the same results. Successful Provisioning, but failed Registration. Let the device sit for 10 hours, it eventually registers successfully.
10) After this waiting game, selecting Sign In will display the Sign in URL and Pair Code.
I've verified there are no firewalls blocking the required sites, protocols, or ports, or proxies in the middle. I'm not ruling out the network yet though. I will try on another network after the holiday break and see if there are any different results. I'm also still working with Premier support...