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:
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:_spf.hostedemail.com 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:
We also recommend whitelisting addresses from trusted senders in Gmail if you continue having issues.
DKIM and DMARC records should also be added, but they are more advanced and need to be uniquely generated by you for your specific use case. We recommend contacting a system administrator for help with creating and inserting these records.
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