Hello there,
Surface hub connects to the exchange using ActiveSync and device ID needs to be allowed. Also, while configuring, it has to be set as regular mailbox and convert it to room mailbox.
You can also try the Surface Hub Hardware Diagnostic tool contains interactive tests which allow you to confirm essential functionality of your Hub is working as expected. In addition to testing hardware, the diagnostic can test the resource account to verify that it is configured properly for your environment.
The below thread discusses the same issue and you can try out some troubleshooting steps from this and see if that helps you to sort the Issue.
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