Why are my Emails Bouncing?

Many of our users who utilize our POP3/IMAP hosted email service have been reporting issues with their emails bouncing or otherwise being undelivered. Specifically, many users are having issues sending email to Gmail addresses, with emails bouncing with the following or similar error:

550-5.7.26 This message does not have authentication information or fails to pass authentication checks. To best protect our users from spam, the message has been blocked.

We are going to do a quick walkthrough of why this is happening and ultimately, how to fix it.

Whether your mail gets accepted by Gmail or not depends on several factors such as content and subject of your email, attachments, and more. In addition, there are also values hidden to a recipient on your domain, like SPF, DKIM and DMARC records. These are verification records added to your domain which tell Gmail and other Email providers who is authorized (or not) to send email from your domain. Without them, anybody can potentially send email from your domain, making Gmail wary of your emails.

For more information on what these records are and what they do, please review this guide: https://www.noip.com/support/knowledgebase/beyond-the-basics-advanced-records-in-dns-configurations/

Here’s a page from Google which explains some of this from their end: https://support.google.com/mail/answer/81126#authentication
SPF Records

The easiest and most effective solution is to add an SPF record to your domain. We provide one so you don’t have to create it yourself:

v=spf1 include:no-ip.com ~all

If your DNS is provided by No-IP, you can add this SPF record yourself on your No-IP dashboard by going to My Services > DNS Records > Modify and click the TXT button. In the Data field paste the SPF record, and click Add. It should look like this:

Screenshot 2024-04-15 at 1.20.11 PM

DKIM and DMARC records while not completely necessary for most users, can also help emails be seen as legitimate and avoid your emails being seen as spam. No-IP has a DKIM and DMARC generator for you to use.


A DKIM record can be generated from the email page in your account. Click Actions > Configure then Setup Now. You will be taken to the DKIM creation wizard. Please make sure to read all of the information and instructions.


You can create a DMARC record from the DNS Records page. Click Modify for the desired hostname then DMARC underneath the “Advanced Records” section. You will be taken to the DMARC creation wizard. Please make sure to read all of the information and instructions.

We also recommend whitelisting addresses from trusted senders in Gmail if you continue having issues.

These measures should help with ensuring your emails are delivered when sending to Gmail addresses. If after completing this process you are still having issues, please contact our No-IP support team by creating a ticket here: https://www.noip.com/ticket