It sounds like the mail profile may might be corrupt or not being read correctly Have u tried rebooting the exchange server?
Hope this helps!
Thanks Schmidtw, even that also i tried , restarted Exchange server, but facing same issue
If you find any sort of corruption, I find it is best to recreate the account entirely.
1. Copy the account. Name is something else.
2. Map both accounts to Outlook
3. Copy all calendar events, notes, emails, etc. to the new account
4. Delete the old account.
5. Rename the new account.
6. With Cached Exchange mode, users may experience issues emailing to this account, so turn off cached exchange have the user send and recieve then turn it back on.