...Failed to retrieve instance list caused by <server_name>: can't fetch instance's properties...
This issue is caused by DS-data corruption.
Please use ResetConfig script or DS reinstalling.
To reset exiting configuration, you can try the following steps:
1. Find and run
c:\Program Files\Quest Software\Diagnostic Server\Agent\bin\ResetConfig.bat
file on the DS-machine;
2. Start "Quest Diagnostic Server" service, wait for 1..2 minutes to finish initialization;
(PLEASE NOTE: all your settings will be lost)
Then run SoSSE client and recreate all the connections.