It has come to our attention that emails are failing to send for newly created addon domains on a cPanel account. This is due to cPanel changing the way addon domains are handled on newer versions of cPanel/WHM. You may refer to this here.
At HostXNow, we use MailChannels to relay emails. Unfortuntely, MailChannels does not fully support the newer version of cPanel/WHM. MailChannels plugin will automatically add/update the correct SPF record for newly created cPanel accounts, but not newly created addon domains due to the changes to how addon domains are managed by cPanel on the cPanel versions v106 and above.
MailChannels were not aware of the issue until we notified them about it. It may take some time for MailChannels to update their plugin to support the changes made by cPanel/WHM.
If you want to send emails from an addon domain on HostXNow servers, you will need to manually update the SPF record as mentioned here.
You may check if the correct entry exists for your domain by checking
https://www.mail-tester.com/spf-dkim-check
Enter the Domain name and for DKIM Selector enter 'default', then click the Check SPF & DKIM keys button.
If the SPF record shows the entry include:relay.mailchannels.net no changes are required on your end.
Please note: if you are using a 3rd party email service like Google or Hotmail it will have its own SPF record and you should not change it. In that case, include:relay.mailchannels.net does not need to be added/updated.