Office 365 - Exchange 2010 Hybrid configuration mail flow issues

We have configured the Hybrid connector between our Office 365 location and Exchange 2010 server and this has completed without error.

However if we e-mail an e-mail address that only exists in one location then we get an NDR from the other (e.g. e-mail address exists on a mailbox in Exchange 2010, we try e-mailing this from Office 365 mailbox and get an NDR from Office 365 that the address does not exist).

If we set a domain to only exist in one location (e.g. the domain only exists in Exchange 2010) and configure this domain if Office 365 to be the 'Internal Relay' type then mail flow works as expected and this can be delivered.

I believe that we are missing something with the Office 365 portal configuration to allow domains to be configured as the 'shared' type (there is no option for this on the 'accepted domains' tab).

Any suggestions on what we might be missing would be greatly appreciated.
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Vasil Michev (MVP)Commented:
Configuring the domains as Internal relay is part of the Hybrid process, not sure how you have missed that. In any case, make sure that any domain shared between the on-prem organization and EO has been verified in O365, its domain intent is set to Exchange and the domain type is set to Internal relay (O365 portal -> Admin -> Exchange -> Mail Flow -> Accepted domains -> double-click the domain -> Internal relay).

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
riverbankAuthor Commented:
Thanks for the help Vasil. Your solution mixed with changing the DNS server fixed the issue
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Office 365

From novice to tech pro — start learning today.