Forum Discussion

Iron Contributor

Mar 09, 2018

Solved

Strange Exchange Online error when sending emails to users that are on another server

Hi, Given that: mycompany.com and mycompany2.com have been added and verified in an Office 365 tenant (mycompany.onmirosoft.com). The MX records of mycompany.com points to mycompany-com.mail....

Haneef Ibn Ahmad
Mar 09, 2018
Actually, just fixed this, by changing the email relay options, as shown here: https://support.office.com/en-us/article/fix-email-delivery-issues-for-error-code-5-1-10-in-office-365-5a04a25a-a34f-476b-afc6-007fb92f86a1?ui=en-US&rs=en-US&ad=US

NunoAriasSilva

MVP

Mar 09, 2018

Hi Haneef,

That is normal issue, you have to change the Authority of your domain name and create an Conector to your On-Premises organization. It's a simple coexistence scenario.

Haneef Ibn Ahmad
Iron Contributor
Mar 09, 2018
Thanks for that.

Changed the authority of the domain, to 'Internal Relay' and the emails are delivering fine now.

Do I still need to setup a Connector?

By the way, thank you very much Nuno, you've been very helpful and swiftly responsive.
- NunoAriasSilva
  MVP
  Mar 09, 2018
  Yes, you will need a connector if you change the MX Record and need to deliver to on-premises system.
  - Haneef Ibn Ahmad
    Iron Contributor
    Mar 10, 2018
    aha, okay! That makes sense.
    
    But, my MX records for mycompany2.com are still pointing to mx.mycompany2.com, it hasn't been changed to mycompany2-com.mail.protection.outlook.com.