There can be a totally uncalled situation where all the emails you send to Gmail addresses are getting flagged as spam. This is an alarming, yet obvious situation if your server is not clean and is blacklisted.
But, if your server is clean, and is free from any blacklists, then you need to make sure if you have IPv6 enabled in Exim.
In Cpanel, ensure that the “disable_ipv6” option has been turned ON. if not, the server will have an IPv6 IP address bound to it, and Exim will send an email out using that IPv6 address. If the SPF record doesn’t have the IPv6 listed, Gmail will see this as an unauthenticated email and flag it as spam.
You can rectify the problem using the following solution:
1. Turns off IPv6 in Exim
You can go to the WHM, then browse to
Exim Configuration Manager >> Advanced Editor
There is an option called “Add additional configuration setting, select “disable_ipv6” from the drop-down list, and set the value to “true”.
After that, click on the save button at the bottom of the page, and you are done.
2. Add IPv6 in the SPF Record
If you want to go by enabling IPv6, then you need to add the new IPv6 IP address to your existing SPF record.
In a full SPF record, it’ll look somewhat like this.
mydomain.com. TXT “spf1 +a +mx +ip4:192.168.1.1 +ip6:fdcf:0851:5144:bff3:xxxx:xxxx:xxxx:xxxx ~all”
Then you can simply replace the ip4 and ip6 with your own IP addresses to fix the problem.