You will receive a “550 No such user” error when you attempt to send an email to an account that does not exist. The error, sent as a bounce back message in your mailbox, will look similar to the following:
This message was created automatically by mail delivery software.
A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed: email@example.com
SMTP error from remote mail server after RCPT TO:<firstname.lastname@example.org>:
host domain.com [18.104.22.168]: 550 No such user
Check the recipient’s email address to ensure it is correct and try sending the email again.
If the email account is hosted with HostPapa and you are sure that it is correct, please open a support ticket from your HostPapa Dashboard. Follow this link to learn how.