Email Error 550: High Probability of Spam

A 550 Spam error is a catchall error message that is relayed back to the user within a bounced message to alert them about why an outgoing message was bounced. The specific error message “550: High probability of spam” occurs when you attempt to send an outgoing email to another mail server and it rejects it outright due to classifying your message as spam.

While it is frustrating that your mail can automatically be classified as spam, this is usually done as a safety precaution by mail servers in order to keep users safe from potential hazards that could slip through a spam filter. While there are ways of preventing this bounce error from occurring on your end, it is generally impossible to completely avoid these types of bounces from occurring due to the nature of not knowing how the spam filters of other mail servers are configured. Lets go over some ways of preventing this error from occurring as well as some troubleshooting methods you can perform to narrow down.

Common Solutions To This Error

While there isn’t a guaranteed way of fixing this issue for your inbox, there are a few things you should try before moving onto other possible solutions.

1. Make Sure SMTP Authentication Is Enabled

SMTP Authentication is the process in which you identify yourself to a mail server you intend to send an email too, before you actually send an email. This is needed for mail clients (Outlook, Thunderbird, etc) to function, as before any outgoing mail can be sent from these types of clients you will need to enable this within the settings of your mail server and client.

If SMTP Authentication is not enabled, this can harm your overall spam score and be enough to trigger spam traps.

2. Ensure The Contents Of Your Email Don’t Read As Spam

Over time, spam filters have become much more aware of the type of language that spammers will use when sending out their mail. Overall, this is a good thing as it means less spam messages reach your inbox, but it’s important to know what language will trigger these spam filters. This is one of the more common causes of the 550 spam error on new/healthy domains as some mail servers will immediately get triggered if the contents of your message contain this language.

We have accumulated a list of known words that trigger spam filters that can be found here. If you are receiving 550 bounce errors pertaining to spam, we strongly recommend removing any words that are found within this list and see if the problem continues.

3. Verify That Your DNS Security Settings Are Properly Setup

Another common reason for having 550 spam errors is due to a lack of the proper security settings under your DNS. Not having SPF, DKIM, and DMARC setup under your domain will drastically affect your deliverability as well as cause spam filters to reject your mail. An easy way to verify that your settings are present within your DNS is to utilize a service such as Mail-Tester to check this.

Start landing in more inboxes. Use Warmup Inbox to increase deliverability and monitor blacklist activity.

Get started today for free.

(no credit card required)