Mysterious MVS Server Outage

We are running the MVS version 2.1, level 0 server as a started
task.  About noon yesterday (4/14) it appears to have stopped
accepting tcp/ip sessions.  There is no indication in the
activity log (or in our systems log) of any tcp/ip communications
problem.  The server was still accepting IUCV requests.  Has
anyone experienced a problem with the server suddenly stopping
listening for tcp/ip (or other requests) but with no error
indiciation in the activity log?  We certainly would like to
know what happened to try to prevent it from occurring again.

Thanks in advance

------------------------------------------------------------------
Robert P. Klein                          KL2 AT CU.NIH DOT GOV
Robert P. Klein                          KL2 AT CU.NIH DOT GOV
Phone: 301-496-7400                      Fax: 301-496-6905
Mail:  DCRT/CFB/ETS, 12A/1033, 12 SOUTH DR MSC 5607,
       BETHESDA, MD 20892-5607
------------------------------------------------------------------
=========================================================================