The proxy address "SMTP:.onmicrosoft.com" is already being used by the proxy addresses or LegacyExchangeDN. Please choose another proxy address.

Bhavneesh Sohal 5 Reputation points
2023-05-03T16:19:01.17+00:00

Hello,

I am trying to create a shared mailbox user@domain1.com in Exchange online but getting error The proxy address is already being used by the proxy addresses or LegacyExchangeDN. Please choose another proxy address.

I have another shared mailbox with same same but different domain user@domai2.com.

How can I resolve this?

Microsoft Exchange Online
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Microsoft Exchange Online Management
Microsoft Exchange Online Management
Microsoft Exchange Online: A Microsoft email and calendaring hosted service.Management: The act or process of organizing, handling, directing or controlling something.
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  2. Kael Yao-MSFT 37,676 Reputation points Microsoft Vendor
    2023-05-04T01:23:13.16+00:00

    Hi @Bhavneesh Sohal

    There is a Microsoft documentation about this error message: Error when creating shared mailboxes

    If you see the error message, The proxy address "smtp:<shared mailbox name>" is already being used by the proxy addresses or LegacyExchangeDN of "<name>". Please choose another proxy address, it means you're trying to give the shared mailbox a name that's already in use. For example, let's say you want shared mailboxes named info@domain1 and info@domain2. There are two ways to do this:

    • Use Exchange Online PowerShell. See this blog post for instructions: Create Shared Mailboxes with Same Alias at Different Domains
    • Name the second shared mailbox something different from the start to get around the error. Then in the admin center, rename the shared mailbox to what you want it to be.

    Please follow the solutions to either use Exchange Online Powershell or use another alias.

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