503 Valid RCPT command must precede DATA when sending emails

When trying to send emails using a mail client, at times it generates following error.
503 Valid RCPT command must precede DATA

Emails are not validated before being sent, which is the cause of the problem.Email hosting companies prohibit sending emails without first requiring a login and password for authentication. These features are activated for security purposes.

If you face similar error, login to your mail client & access the option accounts. Edit the settings OR access Properties tab for the account which shows such error. Find for Servers tab and enable the option My server require authentication.

Click on Apply & Ok. Now, try sending emails.

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