Why are emails not being sent from my Gmail?
Double-check recipients and email details. Make sure you have configured the Gmail server properly. Clear cache and data. Re-install Gmail.
Why is my Gmail not sending emails ?
Check once to whom the mail is being sent. Are their given addresses correct?. If the message contains an incorrect or invalid email address, the message will not be sent. Incorrect SMTP settings. Verify that the settings used for outgoing messages are correct.