Fix SQL Server Availability Group Listener IP Errors and Configure Network Ports

First ensure that the network is reachable and that essential ports such as 5022 and 1433 are open. If a private network is used, it must also be mutually reachable, and a gateway may need to be added.

In SQL Server Management Studio, add a listener IP address. Open the properties dialog and click Add to create a new listener.

Select the appropriate network and subnet. Choose the newly created subnet and configure the desired IP address for the listener.

During failover cluster migration, configure the listener in the cluster manager. Right‑click the red‑boxed area to view dependencies; the default selection is sufficient.

In the same view, you can set the listener to offline or offline mode; for this guide we set it to offline.

During configuration the following error may appear:

Server "xxxxxx" cannot host any IP address for the availability group listener. Either configure a public cluster network that can host the specified IP address, or add another listener IP address that can be hosted on this server's public cluster network.

Additionally, the join operation fails with SQL Server error 19456:

Unable to connect the local availability replica to availability group "xxxxxx". The operation encountered SQL Server error 19456 and was rolled back. See the SQL Server error log for details. After correcting the root cause, retry the ALTER AVAILABILITY GROUP JOIN command. (Microsoft SQL Server, error: 19456)

After applying the above network and listener settings, the error is resolved and the availability group functions correctly.