Hi @abbi,

There could be possible reasons behind the experienced behavior. Let’s first start with making sure your domain has the full priority to send out e-mails and getting the highest possible score on e-mails.

First point

Make sure you have configured SPF, DKIM and DMARC records on your domain. Those 3 records prove authenticity for your server and domain. Without these 3 it will be hard to send e-mails as a whole to every big mail provider. You can check the following article for more information:

https://www.digitalocean.com/community/tutorials/how-to-use-an-spf-record-to-prevent-spoofing-improve-e-mail-reliability

Once you have the above-configured use a mail testing website which will let you know what your e-mail score is. You must make it 10/10. The website I personally use is :

https://www.mail-tester.com/

Second Point

Make sure you are sending authenticated MAILS. If you are using a script or some webmail gui, make sure you are using SSL/TLS encryption with e-mails going out either from port 465 or port 587.

Third and last Point

Make sure your IP address is not blocked and you are not sending out spam messages. You can check your IP address on multiple websites for blacklisting. As for the websites you can search for them on google or any other search website.

If it’s blacklisted, you’ll need to pinpoint where exactly is the spam originating from.

Regards,
KFSys