Hello Anil Sharma,
A 408 Graph service exception is an error that occurs when there is a timeout while trying to establish a connection between a client application and MS graph service. The 408 error indicates that the server timed out due to an issue with the request or with the target resource.
As per my testing, Update Place graph API with delegated permission 'Place.ReadWrite.All' permission is working absolutely fine. Possible reasons you are encountering this 408-service exception could be:
You're trying to update an object that is not a Tenant room, or roomlist.
You're using application permissions/client credentials flow to update the room, which is not supported as per documentation.
Hope this helps.
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