If you are getting the below error - “The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required” 1. Check if you have received an email notification - We recently blocked a sign-in attempt to your Google Account Sign-in attempt details Date & Time: Location: 2. Check this link and acknoledge the sign in attempt as yours - https://security.google.com/ settings/security/activity 3. Go to this link and enable access to less secure applications https://www.google.com/ settings/security/ lesssecureapps