The "Manual Configuration" page outlines manual setup you may need to perform after the secure restore to the target gateway was done:

• Non-mgmt network interfaces should be still disconnected at the target gateway.
  To enable applicative traffic on the target gateway, please configure the source gateway's and/or target gateway's network interfaces in a way that will not cause IP address collisions.
• If the source gateway was part of an API-Connect gateway cluster, you might need to make API-Connect aware of the migration by removing the gateway from the cluster and adding it back again.