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NNL-00006:

timeout, server is not responding
Cause: The control program issued a request to an Oracle Names server and no response arrived in a timely fashion. The network connection between the control program and the server may be faulty, the server may be very heavily loaded, or there may be substantial network delays between the control program and the server. The latter is especially true for WAN links.
Action: Reissue the command; if it continues to fail, check to see that the server being managed is running correctly and that the network connection between the server and the control program is working correctly.