HCW8039 The hybrid Send connector must only contain the single address space error when you run HCW

Original KB number:   3087172

Problem

When you run the Hybrid Configuration wizard (HCW), you receive the following error message:

HCW8039 The hybrid Send connector must only contain the single address space '{0}'

Cause

This issue occurs if the Send connector that the Hybrid Configuration wizard creates has other namespaces added to it.

Solution

To resolve this issue, follow these steps:

1. Open the Exchange Management Shell.

2. Run the following command:

   Get-SendConnector -name "Outbound to Microsoft 365"
   

3. In the output, examine the value of the AddressSpace parameter. You should see either * or contoso.mail.onmicrosoft.com;1.

4. If you see any addresses other than * or contoso.mail.onmicrosoft.com;1, remove them. To do so, run the following command:

   Set-SendConnector -name "Outbound to Microsoft 365 "smtp:contoso.mail.onmicrosoft.com;1"
   

5. Run the Hybrid Configuration wizard again.

More information

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