Client loses connectivity while roaming between two different wireless controllers. Which configuration error causes this?

For seamless client roaming between wireless controllers in a mobility group, all controllers must share the same virtual interface IP address. This virtual IP acts as a common anchor point for client sessions as they transition between access points associated with different controllers. If the virtual interface IP addresses differ, the client's session cannot be maintained across controllers, leading to a loss of connectivity. While a consistent mobility group name is essential for controllers to recognize each other as part of the same group, it doesn't directly cause client connectivity loss during a roam if inconsistent. Having all controllers use the same virtual interface IP is the correct configuration, not an error.