can not login MTR device

[Raymond950]

Our clients in USA Couldn't login MTR device using Room mailbox account licensed with Teams room standard license.

Kindly assist 

[#2]

@Raymond950 I don't really see how anyone could assist given how few details have been given. Perhaps you could describe what troubleshooting has been done already, how the network is configured, what the error they receive says, and what the AzureAD Sign-in log says.

[#3]

To be more specific about the account that has been created for this device.
It is an On-prem AD account with remote mailbox which was later converted to Room mailbox and synced to AAD,
This on-prem account has been set with password to never expire.
Microsoft Teams room standard license has also been assigned.
The account is logging in fine when used on Microsoft Teams Web client on a browser.

Error been received:: Couldn't sign in to Microsoft Teams
This is a new device that we are trying to login and the accounts were also newly created