New MTR devices unable to connect workplace

This error is commonly related to Azure AD Workplace Join / Intune enrollment prerequisites rather than the device itself.

For Poly MTR devices, I would first validate the following areas:

• Correct date/time and NTP synchronization
• DNS resolution for Microsoft endpoints
• TLS inspection / SSL interception on firewall or proxy
• Modern authentication support
• Conditional Access policies
• Intune / Teams Rooms enrollment restrictions
• Device firmware version compatibility

The “Couldn't connect to Workplace Join” error is often caused by:

• blocked Microsoft enrollment endpoints,
• SSL inspection,
• or Conditional Access requiring compliant/hybrid-joined devices.

Things I would specifically check:

1. Microsoft endpoints accessibility
   Make sure these are reachable without interception:

• login.microsoftonline.com
• device.login.microsoftonline.com
• enterpriseregistration.windows.net
• teams.microsoft.com

1. TLS inspection
   Poly devices are very sensitive to SSL inspection/proxy rewriting.
   If your firewall performs HTTPS inspection, try bypassing Microsoft 365 endpoints temporarily.
2. Entra ID device settings
   Verify:
   Entra Admin Center → Devices → Device Settings

• Users may join devices to Microsoft Entra = All/Selected
• Device limit not exceeded

1. Conditional Access
   Temporarily exclude:

• Microsoft Teams Rooms devices
• Android-based Teams devices (if applicable)
  from strict CA policies for testing.

1. Firmware
   Several older Poly firmware builds had Workplace Join/authentication issues.
   I would strongly recommend updating:

• Poly X52
• TC10
• Trio 60
  to the latest Teams certified firmware.

1. Licensing
   Confirm the resource account has:

• Teams Rooms license
• Exchange Online mailbox
• Teams enabled

If both systems fail on the same VLAN, the issue is usually:

• network inspection,
• DNS/proxy,
• or Entra enrollment policy related,
  rather than hardware failure.