Recently, I got asked to assist with a Hybrid Configuration Wizard which was failing with the following error message:

Updating hybrid configuration failed with error ‎’Subtask NeedsConfiguration execution failed: Configure Mail Flow Default Receive Connector cannot be found on server <server name>. at Microsoft.Exchange.Management.Hybrid.MailFlowTask.DoOnPremisesReceiveConnectorNeedConfiguration‎()‎ at…

Although the message might not reveal much information at first sight, it does contain everything we need to start troubleshooting. Typically, I would suggest you go and have a look into the Hybrid Configuration Wizard log files (located in the logging\Update-HybridConfiguration folder), but the only thing you would find there is the exact same error message.

First, we know that the HCW is trying to configure the hybrid mail flow and that it failed trying to modify the default connector that’s in place. More specifically, it was trying to modify the receive connector on the server that’s specified in the error message.

In this particular case, it wasn’t even able to find the Default Receive Connector. However, when you run the Get-ReceiveConnector -Server <servername>, the receive connector does show up. How is this possible?

The Hybrid Configuration Wizard looks at more specifics than just the existence of the connector. In fact, it will check that the connector’s configuration is valid as well. As such, it will check the bindings on the connector and expect that both bindings for IPv4 and IPv6 are present. So to check whether your existing connector is valid, you should run the following command:

Get-ReceiveConnector -Server <servername> | fl Identity,Bindings

receiveconnector

In this particular case, the IPv6 bindings were missing. This was caused because IPv6 was disabled on the server (which shouldn’t be!). Re-enabling IPv6 and then either manually adding the binding to the connector or re-creating the connector solved the issue.

The morale here is that you shouldn’t disable IPv6 on an Exchange 2013 box. Even more so, it’s not supported if you do. I’ve seen companies that still disable IPv6 by default; maybe a remainder from earlier times where disabling IPv6 would actually solve issues instead of creating them. However, times have changed and the IPv6 implementation in Windows is much better now…