How to Update Proxy Addresses for a Cloud-Only Object

Problem

If you want to add or remove (basically update) a proxy address on a cloud-only account - without an Exchange mailbox - you cannot.

There is no such option in the GUI and PowerShell won’t allow it either, throwing an error:

Set-MgUser : Property 'proxyAddresses' is read-only and cannot be set.
Status: 400 (BadRequest)
ErrorCode: Request_BadRequest

Solution

Use the Graph API BETA endpoint.

• Method: PATCH
• URL: https://graph.microsoft.com/beta/users/<User_ID>
• Request Body:

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{
    "proxyAddresses": [
        "SMTP:PrimarySMTPAddress",
        "smtp:Alias1",
        "smtp:Alias2",
        "smtp:Alias3"
    ]
}

• Expected Response: 204 No Content

Tip

You can first retrieve the existing proxy addresses and paste them into the Request Body, then add or remove the entries you need.

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https://graph.microsoft.com/beta/users/<User_ID>?$select=proxyAddresses