I am getting an error while trying to send the followup.

[devicode]

Description:

When sending mail, the error message "550 or 553 Relay Denied" is given by the SMTP server and mail cannot go out.
Many smtp servers use some sort of protection against email spamming. This only allows trusted users or computers to send email via the server.

Possible Causes:
1) The SMTP server does not allow relaying unless you are sending email from a trusted IP or use proper authentication.
2) The server is setup to block smtp relaying.
3) Some servers allow you to send email internally but not to external email addresses.
4) Some SMTP servers require the Email User to login and check their POP3 email at least once on the given IP before they let that user send SMTP mail from that IP. Once the POP3 email is checked using a valid user/pwd, the computers IP is then automatically added to a safe list on the server. This is another way to prevent spamming.
5) Relaying denied is a common safety measure used by SMTP servers when a certain email address & its mail server are put on a blacklist for email relay spam violations.

Solution
Possible solutions:
1. Some email servers may allow relaying only if you log in and check email atleast once from a given IP address. In this case, you can check your POP3 email first before sending SMTP email from a new computer.
2. Some email servers allow smtp relaying only if you log in and check email within the last 1 hour/day etc... In this case, you should use the pop3 authentication method to send email.
3. Some servers require you to authenticate before sending email. In this case, use the Secure or Plain authentication methods.