How to fix mandrill / mailchimp transactional email issue recipient-domain-mismatch

Question

Mandrill is rejecting any emails sent to a domain that doesn't match my verified domain but it's not clear why this is happening.

How do I allow outgoing email to be sent to any public domain such as gmail that won't match my domain?

Answer 1

There is two possible cause for this issue:

- 1. You're on a Trial plan (aka DEMO MODE)

While in demo mode, you can only send to verified sending domains that you've added to the account. This restriction is lifted when blocks are purchased and the account is fully activated.

- 2. Your DNS settings are incorrect

Your mail will be rejected unless sent from a verified domain with valid DNS records. 

Here are two articles related to those issues:

• https://mandrill.zendesk.com/hc/en-us/articles/360049504074-Mailchimp-Transactional-Email-Demo
• https://mandrill.zendesk.com/hc/en-us/articles/360038743494-How-to-Set-up-Sending-Domains

Having the right setting for DKIM is also very important. In my case I was actually dealing with both issues.

The status of my DNS Setting when I posted this issue were:

• Verified Domain ✅
• DKIM valid ✅
• SPF valid ✅

To confirm if you have DNS issues:

1. Go to Settings > Domain >
2. click on 'Test DNS Settings'

When I did that it updated my ✅ valid DNS setting to invalid ❌. Turns out, I had entered the full « mandrill._domainkey.example.com » for the NAME of my TXT in the record, instead of «  mandrill._domainkey ». So my DKIM wasn’t "missing" BUT it was invalid; which updated the status to DKIM valid.:

That happened because when I first set my DKIM settings I forgot to recheck after 60 minutes.

Your DKIM record is valid, but it will take a bit for DNS providers to all see that it is. We'll recheck your record in 60 minutes.

SUMMARY

If you don't want to run into the same issue. When you first setup your account; Make sure to click 'Test DNS Settings' after 60min to confirm that your DNS settings are still « valid » and make sure that you're using a PAID subscription since in DEMO mode, you can't send email outside our verified domains.