What causes '550 relaying denied' bounce errors and how to resolve them?

Email marketer from cPanel Forum says to check that you have the correct authentication method set up. For example, with Gmail, you will likely want to use the TLS.

Email marketer from Digital Ocean explains that this type of error can occur from issues related to the hostname not being properly configured and the local server being unable to resolve the domain.

Email marketer from Reddit mentions that a common cause is attempting to send email directly to a recipient's mail server without proper authentication or authorization. Using an SMTP relay service can often resolve this issue.

Email marketer from MXToolbox suggests that the 'Relaying denied' error may occur when your IP address is blacklisted. Checking your IP against common email blacklists and requesting removal can help resolve the issue.

Email marketer from StackOverflow shares that ensuring your sending IP address has a valid reverse DNS (PTR) record that matches your sending domain can help resolve 'Relay access denied' errors, as it helps establish trust with receiving mail servers.

Email marketer from Mailjet advises to ensure your email client or application is configured to use SMTP authentication. This involves providing a valid username and password for your email account when sending emails.

Email marketer from SuperUser suggests to verify the 'From:' address is a valid address for your mail server. In other words, make sure you are sending using an email address associated with your server, and not a third party.

Expert from Email Geeks confirms the VMG errors have been rolled back and advises retrying the addresses.

Expert from Email Geeks suggests the cause of relaying denied errors could be DNS caching issues, incorrect MTA configurations, or a problem on Yahoo's end. He recommends checking the MTA config first and examining logs for the IP address of the rejecting server.

Expert from Email Geeks explains that 'Relaying denied' usually means the MX server doesn't handle mail for the recipient address.

Expert from Spamresource indicates that reverse DNS records not matching the outgoing mailserver address, incorrect HELO/EHLO configurations can lead to relaying denied errors. These checks are done to verify the sender's legitimacy.

Expert from Word to the Wise explains that the specific error message and reason code can provide clues as to why relaying is denied. Often, it involves sender authentication issues or the recipient domain's policy.

Documentation from Microsoft explains that if you are using Microsoft 365, this error might occur if the sender's email address is not configured as an accepted domain in your Microsoft 365 account. Adding the sender's domain to the accepted domains list can resolve the issue.

Documentation from Google explains that you need to check your Google Workspace email relay settings. Make sure the sending IP address or domain is authorized to relay emails through your Google Workspace account.

Documentation from Exim explains this error in more technical detail relating to the specifics of Exim based mail systems and to check the main configuration.

Documentation from SendGrid advises that using a dedicated SMTP relay service like SendGrid, and configuring your application or email client to use their SMTP servers, will handle authentication and prevent relaying denied errors. This ensures proper email delivery.

Documentation from cPanel explains that 'Relaying denied' errors occur when the mail server you're trying to use isn't authorized to send emails on behalf of the domain you're using. This often happens when sending emails from a script or application without proper authentication.

Documentation from Postfix explains that the error may be due to incorrect relay settings in your Postfix configuration file (main.cf). Reviewing and correcting the 'relayhost' and 'mydestination' parameters can prevent this error.