Failing Test-ReplicationHealth but DAG is up

We're having trouble on our three node DAG which seems to be in good health. We have an error that says:

[PS] C:\Windows\system32>Test-ReplicationHealth

Server          Check                      Result     Error
------          -----                      ------     -----
MAIL2           ClusterService             Passed
MAIL2           ReplayService              Passed
MAIL2           ActiveManager              Passed
MAIL2           TasksRpcListener           Passed
MAIL2           TcpListener                Passed
MAIL2           DagMembersUp               Passed
MAIL2           ClusterNetwork             Passed
MAIL2           QuorumGroup                *FAILED*   Quorum resource 'Cluster Group' is not online on server 'mail2...
MAIL2           DBCopySuspended            Passed
MAIL2           DBCopyFailed               Passed
MAIL2           DBInitializing             Passed
MAIL2           DBDisconnected             Passed
MAIL2           DBLogCopyKeepingUp         Passed
MAIL2           DBLogReplayKeepingUp       Passed

Two nodes are on-site and one offsite on a separate LAN through a VPN. We're able to switch databases around without any fault or errors and the database replication always shows as Healthy.

Why is the QuorumGroup failing? I can PING the server hosting the FSW folder from any of the three nodes.