This article will guide you on the causes and different methods to solve SMTP #error #10051 which occurs due to improper #SMTP authentication, ISP #firewall issues, #Antivirus on #PC, and so on. You can generally find your SMTP server address in the account or settings section of your mail client.) When you send an email, the SMTP server processes your email, decides which server to send the message to, and relays the message to that server.
To fix email not connecting to server:
1. Check your internet connection.
2. Check your SMTP server details.
3. Verify all usernames and passwords.
4. Check your SMTP server connection.
5. Change your SMTP port.
6. Control your antivirus or firewall settings.