If you have ever seen it, you might ask, “What causes the “550 Permanent Failure for One of More Recipients” error?”

What is the “550 Permanent Failure for One or More Recipients” error?

An SMTP 550 permanent failure is one of the most common errors email users will see. The SMTP 550 Permanent Failure is linked to the Simple Mail Transfer Protocol (SMTP) blocked email issue.

Is the “550 Permanent Failure for One or More Recipients” a sender or recipient error?

Generally, “550 Permanent Failure for One or More Recipients” is caused by the email recipient.

What causes SMTP 550 Permanent Failure error code?

You may encounter the “550 Permanent Failure for One or More Recipients” error when:

  • The email recipient’s email host server blocks the IP address of your SMTP server.
  • The hosting SMTP server marks your email message as spam, mistakenly or correctly, and blocks your email.
  • A domain name is either blocked or invalid.
  • The recipient can’t receive email due to a full inbox.
  • The recipient’s email either doesn’t exist or is found.
  • The recipient’s email is temporarily disabled or suspended.
  • The hosting server is unavailable.

What does 550 Permanent failure for one or more recipients mean?

An SMTP 550 error code can be written in multiple different ways. The wording of a 550 error code depends on the sending SMTP email server.

Here are a few examples of 550 errors you may see:

  • SMTP Error 550
  • 550 User account is unavailable – You get this 550 error when the recipient’s SMTP server blocks your email message.
  • 550 Authentication is Required for Relay – You would see this 550 error when the email server requires SMTP authentication to send outgoing mail, but the email client used to send email has not been authenticated with your username and password
  • 550 Address rejected – When the recipient’s mail server blocked your email, you would get this 550 error.
  • SMTP Error 5.5.0 – SMTP Error 5.5.0 means that email can’t be delivered because the mailbox is unavailable.
  • 550 Invalid recipient – You would see this 550 error when an email was sent to an email address that doesn’t exist.
  • 550 – Requested actions not taken as the mailbox is unavailable.
  • 550 No such user here – If you typed an email address incorrectly, you would get the error, 550 No such user here.
  • 550 Not our Customer – If you send an email to an email address that doesn’t exist on the recipient’s SMTP server, you will get the “550 Not our Customer” error.
  • 550 Account not available – When a username is either inaccessible or not found on the receiving email server, you would get the “550 Account not available” error.
  • Remote host said: 550 – [email protected], this windows10store.com
  • Mailbox Does Not Exist – Giving up

How to troubleshoot a 550 Blocked error?

An SMTP 550 Error is generally an error on the recipient’s side. But, you may be able to resolve 550 errors.

Here are some tips for troubleshooting 550 blocker errors:

  • Confirm that you correctly spelled the recipient’s email address. If you don’t send a valid email address, you will get a 550 error. Avoid extra spaces, typos and misspellings in emails to get rid of 550 blocked errors.
  • Check with the email recipient to ensure you have the correct email. If you know for a fact that you have the right email address and you still receive a 550 error, the recipient may have sent you a misspelled address. It’s also possible that the user has changed his email address and didn’t update you on it.
  • Check your email address and message. Ensure that your sender email is typed correctly, and check that your email has content. Some email hosting servers are set up to reject no content or blank email messages.
  • Change the outgoing mail port to either 465 or 26. Some SMTP servers block port 25 in an attempt to control spam. Spammers usually use port 25 to send spam.
  • Scan your computer for viruses and malware. Technically, email addresses can’t get infected with viruses, but computers do. Therefore, you should always run a reliable antivirus program on your computer. It’s smart to change your password every couple of months to keep your email account secure.
  • Resend your email. SMTP servers, like any other server, can be unreachable at times. For example, the server may be temporarily down and may come back online after a few minutes. However, if you get the 550 error message several times, contact the recipient and inform them that their email hosting may be experiencing reliability issues.
  • Use the ISP’s outgoing SMTP server. Sometimes, your Internet gateway filters or Internet Service Provider blocks your email messages. You can use your ISP’s outgoing SMTP server to test for this.
  • Ask your ISP for help. What may seem like a really difficult problem for you to solve could be easily resolved with the help of your internet service provider. After all, they are the experts, and they can help you troubleshoot 550 errors.
  • Use strong passwords. Always use a strong password for your email account to keep unauthorized users out of your account. Use two-factor authentication to keep your email account secure. And as an added protection, change your passwords often.

How to fix 550 Permanent Failure Blocked error?

To fix the 550 Permanent Failure Blocked error, you must check if your IP address is blacklisted. That is the IP address of your SMTP server. When the SMTP’s server’s IP address is blacklisted, the recipient’s SMTP server will block your email.

This is very common in shared hosting environments. That’s because hundreds, even thousands of different domains use the same SMTP server. Therefore, if one domain sends spam emails frequently using the shared SMTP server, once its IP address is blacklisted, all domains are blocked.

There is an entire industry built on blocking spam email messages. They filter emails based on blacklisted SMTP server IP addresses. These companies maintain a list of blacklisted email servers. Once an SMTP server’s IP address is blacklisted, its emails will be blocked by many other SMTP servers, triggering a “550 permanent failure for one or more recipients” error.

What to do to fix the 550 Permanent Failure Blocked error?

The first step required to fix the 550 Permanent Failure Blocked error is to confirm that your email server’s IP address has been blacklisted. You can check if your SMTP server’s IP address is on a blacklist by using one of the free online email blacklist checkers like MXToolbox. Using a blacklist checker will help you determine if someone has been sending spam emails from your email server.

Once you have confirmed that your email server’s IP address is on a blacklist, you can take action. Unfortunately, this gets more complicated by the fact that there are many different blacklists. And if your IP address is on multiple SMTP blacklists, you need to whitelist your IP on all of them.

If you host your own SMTP server, you can contact each blacklist. Their websites have blacklist removal request forms. Once you have used their site to confirm that your IP address is on their blacklist, you can submit a request to have yours removed.

And if you are using a shared SMTP server, you can contact their tech support department and ask them to work on whitelisting their IP address. Unfortunately, it’s very common for shared SMTP servers to be blacklisted. When hundreds or thousands of domains use the same email server, sooner or later, one of them will get the email server blacklisted.

Bad Domain SPF record and 550 Permanent Failure

A bad SPF record can cause a 550 Permanent Failure. If you want to prevent this email error, you need to correct the SPF record on your domain. What complicates this 550 Permanent Failure error is that even though it’s shown on the recipient side, the only way to resolve it is to fix it on your (sender) end.

How to fix the SPF record to avoid 550 Permanent Failure errors?

To fix the Sender Policy Framework (SPF) record to avoid the 550 Permanent Failure error, you need to make a change in the DNS record of the sending domain. An SPF record is defined in the DNS zone file. It is a TXT record that specifies the email servers that are permitted to send emails for your email domain.

Reputable SMTP servers use Security Policy Framework to show the authenticity of the sender’s email. If you try to send an email from an SMTP server with a bad domain SPF, your emails will be marked as spam and rejected.

How do I fix a 550 error?

To check the SPF record for your domain, visit https://mxtoolbox.com/spf.aspx. It’s a simple process to check an SPF record. You type in your domain name and click “SPF Lookup.”

In the results, you will see a line of characters, starting with “v=spf1”. Having a valid SPF record for your domain will help improve the deliverability of your email and fix 550 Permanent Failure errors.

What is 550 permanent failure for one or more recipients blocked Gmail?

The 550 permanent failure for one or more recipients blocked Gmail error means that the email you sent was blocked by a Gmail SMTP server and returned to you.

Closing thoughts 550 Permanent Failure error

550 Permanent Failure errors are caused by several issues, from blacklisted SMTP servers to invalid email addresses. Most 550 errors are easy to fix if you understand the source of the problem. Once you identify the issue, you can take steps to resolve it to eliminate 550 Permanent Failure errors and get your emails delivered every time.

550 Permanent Failure Barracuda

Some people and companies struggle to send emails to users behind Barracuda email filtered domains. Users report that they are told they don’t have the correct PTR record even if their PTR record is correctly configured. In other words, people complain that Barracuda is blocking legit emails -reply 550 permanent failure for one or more recipients.