iManager might hang or time out while trying to connect to a server with the Cluster plug-in or the Storage plug-in. Error 500 is reported. This error can occur if your login user name for iManager is not a user that is enabled with Linux User Management (LUM) on the target server.
To avoid this problem, ensure that the user name is LUM enabled on the target server. The Cluster plug-in connects to the master node in the cluster (that is, the node hosting the Master IP Resource).
For more information, see Technical Information Document: iManager error 500 while trying to managing cluster, storage, user quotas, CIFS, or AFP (TID 7010295) in the OpenText Technical Support.