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Few things are more frustrating than the 550 error message – besides, possibly, a broken coffee machine! Let’s dig into what this cryptic message means and how you can resolve it.

550 Error, What?!

You will often see a 550 error accompanied by a small (yet arguably mystifying) message, such as “administrative prohibition” or “relay access denied”. While the message itself is far from clear, the reason behind the error message is usually pretty simple.

This bounce error is generated when the recipient mail server (that is your recipient’s email host or mail program, FYI) has blocked your email. They are rejecting it because you have not given our service “consent” to relay mail on your behalf.

Why does SMTP2GO need consent?

At SMTP2GO we are a relay service. Email originates from your mail program, server, or computer and we relay it through our servers and IP addresses to its final destination: the recipient mailbox. But if you have not given us consent to relay mail on your behalf through our servers, then we would have no business relaying your mail.

Think about it this way: if we were a hypothetical malicious third party and somehow managed to intercept your mail and relay it through our servers onto its final destination, that would be very, very bad. We could change the content of your mail or spoof it, ultimately sending your recipient an email that looked like it was coming straight from you, but was tampered with along the way.

The 550 error message is basically a security feature that the recipient mail server uses when it sees a third party sending on behalf of another sender. It doesn’t know that we have permission to send on your behalf so in order to protect the recipient from harm – or spam/a virus – it blocks our email.

How can I consent?

We’ve made this part as easy as possible for our users. All you have to do is verify your domain in our dashboard. We will provide you with three CNAME records that you will copy/paste into your domain name admin dashboard. This is akin to you giving our service explicit permission to relay on your behalf. It is almost like an electronic handshake, where both of us agree to work together and collaborate to get your email where it needs to go!

We have a step-by-step guide here and our award-winning support team is always available to answer the phone, an email, or instant chat to walk you through the process: Verified Senders.

In compliance with industry standards, we are moving to make verified domains mandatory for all of our users. Ultimately, this is in your best interest as it increases security for you and leads to wildly better deliverability rates.

If the error persists it is generally because the recipient mail server needs to add our IP range to their allow list. At SMTP2GO we have thousands of IP addresses that we own and relay mail from. Some mail servers have strict protocols and only allow email through when it is sent from trusted IP addresses. In this case, you can get your recipient to add our entire range to their allow list.

Note: High-volume accounts (100K and over) have their own dedicated IP. Their recipients will only need to add their sending IP to the allow list, not our entire range!

Check the Settings > Dedicated IPs section of the account’s dashboard to identify the correct address(es) to whitelist!

If you have any questions regarding email delivery issues, please feel free to get in touch with our award-winning support team.

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