Mails from Communication Service are quarantined

@Mathias Indermuehle I can see three items that might be causing issues here.

1. MX Records

Azure Communication Services typically don’t require an MX record for sending emails, as MX records are used for receiving emails. However, if you’re getting flagged for missing MX records, it might be due to how Office 365 is interpreting your domain setup.

To resolve this:

• Set up a basic MX record: Even if you don’t have a mail server, you can set up an MX record pointing to a non-existent mail server to satisfy the requirement. For example:

yourdomain.com.  3600  IN  MX  10  mail.yourdomain.com.

This won’t affect your ACS email sending but will help pass the MX record check.

2. Reverse DNS and Sending Domain Mismatch

The mismatch between your reverse DNS and sending domain can cause emails to be flagged as spam. This is a common issue with shared IP addresses.

To address this:

• Ensure your reverse DNS matches your sending domain: You might need to contact Azure support to configure the reverse DNS settings correctly. The reverse DNS should point to the same domain as your sending domain.

3. DKIM Authentication

DKIM (DomainKeys Identified Mail) is crucial for email authentication. The issue you’re facing with the DKIM body hash not verifying could be due to incorrect DKIM setup or email body modifications.

To fix this:

• Verify DKIM setup: Ensure that your DKIM records are correctly set up in your DNS. You can use tools like MXToolbox to verify your DKIM records.
• Check email content: Ensure that the email content isn’t being modified after DKIM signing. This can happen if intermediate servers alter the email. 1. MX Records Azure Communication Services typically don’t require an MX record for sending emails, as MX records are used for receiving emails. However, if you’re getting flagged for missing MX records, it might be due to how Office 365 is interpreting your domain setup. To resolve this:
  • Set up a basic MX record: Even if you don’t have a mail server, you can set up an MX record pointing to a non-existent mail server to satisfy the requirement. For example:

       yourdomain.com.  3600  IN  MX  10  mail.yourdomain.com.
  

  This won’t affect your ACS email sending but will help pass the MX record check. 2. Reverse DNS and Sending Domain Mismatch The mismatch between your reverse DNS and sending domain can cause emails to be flagged as spam. This is a common issue with shared IP addresses. To address this:
  • Ensure your reverse DNS matches your sending domain: You might need to contact Azure support to configure the reverse DNS settings correctly. The reverse DNS should point to the same domain as your sending domain.
  3. DKIM Authentication DKIM (DomainKeys Identified Mail) is crucial for email authentication. The issue you’re facing with the DKIM body hash not verifying could be due to incorrect DKIM setup or email body modifications. To fix this:
  • Verify DKIM setup: Ensure that your DKIM records are correctly set up in your DNS. You can use tools like MXToolbox to verify your DKIM records.
  • Check email content: Ensure that the email content isn’t being modified after DKIM signing. This can happen if intermediate servers alter the email.