Cannot connect to the database!

Hello,
I am unable to connect the database.
if i use sqlplus, after giving me the release and copyright information, it does not do anything. no error message.

SQL*Plus: Release 8.1.7.0.0 - Production on Fri Jun 7 12:54:53 2002

(c) Copyright 2000 Oracle Corporation. All rights reserved.

if i use svrmgrl
i am able to connect as internal user but not as anyother user. the same problem, no error message, no time out nothing.

sqlnet.log does not give any message.
tnsping works fine.

This happened all of a sudden. it was a properly working system.

After this i restarted the Database and now everything is working fine.

what could cause such a problem.

system config:
Win NT (microsoft cluster server), 2 GB ram, lot of free harddisk space oracle 8.1.7.3
MTS enabled.
OS authentication enabled.
All connections from server use dedicated server (use_dedicated_server=ON), SQLNET_AUTHENTICATION.SERVICES=(NTS)
all clients use shared server. all clients have #SQLNET_AUTHENTICATION.SERVICES=(NTS) , its commented, to solve MTS related bug in 8.1.7

any idea what went wrong.

warm regards,
Pinto. Received on Fri Jun 07 2002 - 02:44:48 CDT