Client Access Express error

[mossing]

The two most common causes of this problem are: The server is down The server is restricted by an exit pgm I will continue my investigation and will update this thread with new information as it becomes available. For further help solving your problem, contact IBM Service.

[Guest.Visitor]

CA gave me the following message: "Error occured while retrieving usage information for USER_ID on TCP/IP address". Where should I look for solution? Can I get second level message? Thanks.