Outlook application is not getting update from exchange server.

Performed actions

1. New profile creation did not work.
2. Outlook was not connecting in online and in cache mode as well.
3. We took the backup of old ost files and again re-created a new profile but still no go.
4. Outlook was not connecting in safe mode as well.
5. Tried VPN Off and On as well but still outlook was not connecting.
6. Office outlook package was already installed again but again the same issue.
7. Outlook application in Virtual desktop is working fine.

If it is a system specific issue,  is there anyone could tell me the ralated system issue ?