550 5.7.1 error when sending email

What is a 550 5.7.1 error?

A 550 5.7.1 commonly refers to the IP sending the email, currently blocked from the recipient's email service.  It is normally blocked because the IP was used to send spam to the recipient's IP at one point in time.  If this example is the case, the recipient's email service blocks the IP from future spam and notifies any senders with a 550 – 5.7.1kick-back somewhere in the returned email.

Is My IP Blacklisted?

Just because you received a 550 – 5.7.1 error does not mean your IP is blacklisted.  However, it is still good practice to check your IP for blacklisting and its current reputation if you received a 550 error for verification.  Please note, this is not the IP from your local machine but the IP of your hosting server.

Tools For Blacklisting Check:

• MXToolBox: https://mxtoolbox.com/blacklists.aspx
• MultiRBL.valli.org Blacklist Checker: https://multirbl.valli.org/

Tools For IP Reputation:

• Cyren: https://www.cyren.com/security-center/ip-reputation-check
• Talos: https://talosintelligence.com/reputation_center

Immediate Steps

It is important to understand why this error occurs and take preventative measures to ensure this can be resolved as quickly as possible. We suggest performing the following:

• Change your Email Account's passwords to a secure password
• Update any Applications that you are using for your web hosting services
• Remove any unused Applications that you are no longer using
• Perform a virus scan on your computer

If you have done these steps and your IP comes back as blacklisted, please open a ticket with our technical support to remove the IP from the blacklist with any relevant email headers from these bounce-back messages.

How do I remove the 550 5.7.1 error?

Unfortunately, if your IP is not blacklisted, a "delist" request to the recipient's mail service is required.   This includes a form with the required information to be submitted explaining their service currently blocks the IP, and you wish for it to be unblocked.  The delist form is different for each mail service (example, Outlook, Gmail), and once submitted, it is up to the current mail service to unblock the IP from their list.

Each email service has its own individual form to be filled out for delisting.  Hostwinds technical support will gladly assist with requesting the delisting of your IP upon opening a ticket and requesting the IP be delisted for any of your Managed Services such as Shared Hosting, Business Hosting, Managed Linux, Managed Windows, or a Dedicated Server.

How long will a delist request take once submitted?

This can vary depending on the results of your IP reputation.  It is important to note that the request is solely in the hands of the delist's service.  If the IP is never delisted from their service and the IP itself is not blacklisted, a 550 7.5.1 error will continue to be kick-backed.

If we can help you in any way, please submit a ticket, or join us in a LiveChat anytime. We are available 24/7/365, and we are dedicated to our client's success; every client truly matters to us.