REJECTED - Bad HELO - Host impersonating

1. What is the issue? Please be detailed.
I have my ODK installation on one server, and my mail server on another. But both have the same domain (

The ODK installation is pointed at by and the mail server is being pointed by

So when the ODK ( tries to send an email to an email ( with the same domain it results in the "REJECTED - Bad HELO - Host impersonating"

So my question, what can be done from odk to overcome this error?

2. What steps can we take to reproduce this issue?

Sending an email from ODK server to an email with same domain name as the ODK server

3. What have you tried to fix the issue?
Tried to diable the spam filter from my email server to accept emails from

4. Upload any forms or screenshots you can share publicly below.


To solve delivery issues, we strongly recommend using a dedicated email service such as Mailjet. Central doesn't send many emails, so such a service will generally be a cost-effective way of ensuring email delivery. Once you have an account set up, you will need to configure Central to use it.

If you do not want to use a dedicated email service, you can try directly sending emails from your Central installation. Configure DKIM to increase the likelihood of your emails being delivered.

The mail-tester service can help you identify what barriers to email delivery you might have. Create a Central account with the email address that it provides, retrieve your results, and then retire the user.

More at

Hello Yan,

Thanks for the response, Could you briefly let me know how to configure the mailing service with MailJet. I don't see it mentioned in the manuals.

Thank you so much, Big fan of your work also.