1. Register an important send/receive library file. Go to Start > Run and type regsvr32 inetcomm.dll
2. Check if antivirus email check is slowing sending and receiving. Disable it.
3. In the account settings, Advanced settings, change the server timeout time from 1 min to 5 min
4. Check if outgoing mail server authentication is required. Select that option in account settings and use same settings as incoming server
5. Your ISP may be blocking port 25. Try using alternate port 587.
6. Check with email provider Tech Support to determine if server is having trouble.
Repair Outlook by following instructions at:
For more details check this out: