Exchange Mail Flow & Domains

%3CLINGO-SUB%20id%3D%22lingo-sub-2287745%22%20slang%3D%22en-US%22%3EExchange%20Mail%20Flow%20%26amp%3B%20Domains%3C%2FLINGO-SUB%3E%3CLINGO-BODY%20id%3D%22lingo-body-2287745%22%20slang%3D%22en-US%22%3E%3CP%3EHi%20guys%2C%20I%20hope%20you%20are%20all%20keeping%20well%20and%20safe.%3C%2FP%3E%3CP%3EI%20have%20a%20small%20challenge%20with%20my%20exchange%2C%20I%20hope%20to%20get%20some%20help%20here.%3C%2FP%3E%3CP%3EThis%20is%20my%20situation.%3C%2FP%3E%3CP%3EI%20have%203%20domains%20D1%20(primary%20domain)%2C%20D2%20and%20D3%20all%20added%20on%20Microsoft%20exchange%20under%20one%20account.%20D1%20has%20its%20mailbox%20on%20Exchange%20whereas%20D2%20and%20D3%20their%20mailboxes%20are%20on%20host-gator%20servers.%3C%2FP%3E%3CP%3EFor%20pilot%20test%2C%20I%20licensed%20several%20users%20on%20D1%20since%20its%20the%20primary%20domain.%3C%2FP%3E%3CP%3ENow%2C%20when%20I%20send%20email%20from%20D1%20(primary%20email)%20to%20D3%20am%20getting%20bounce%20back.%3C%2FP%3E%3CP%3EAnother%20case%3A%20When%20I%20send%20from%20D1%20to%20D2%20am%20not%20getting%20bounce%20back%20but%20they%20are%20not%20getting%20delivered%20on%20the%20other%20side.%3C%2FP%3E%3CP%3EWhat%20could%20be%20the%20issue%3F%3C%2FP%3E%3C%2FLINGO-BODY%3E%3CLINGO-LABS%20id%3D%22lingo-labs-2287745%22%20slang%3D%22en-US%22%3E%3CLINGO-LABEL%3EAdmin%3C%2FLINGO-LABEL%3E%3CLINGO-LABEL%3EExchange%20Online%3C%2FLINGO-LABEL%3E%3CLINGO-LABEL%3EOffice%20365%3C%2FLINGO-LABEL%3E%3CLINGO-LABEL%3EOutlook%3C%2FLINGO-LABEL%3E%3C%2FLINGO-LABS%3E%3CLINGO-SUB%20id%3D%22lingo-sub-2288347%22%20slang%3D%22en-US%22%3ERe%3A%20Exchange%20Mail%20Flow%20%26amp%3B%20Domains%3C%2FLINGO-SUB%3E%3CLINGO-BODY%20id%3D%22lingo-body-2288347%22%20slang%3D%22en-US%22%3EYou%20need%20to%20set%20the%20domain%20intent%20for%20said%20domains%20to%20Internal%20relay%3A%20%3CA%20href%3D%22https%3A%2F%2Fdocs.microsoft.com%2Fen-us%2Fexchange%2Fmail-flow-best-practices%2Fmanage-accepted-domains%2Fmanage-accepted-domains%22%20target%3D%22_blank%22%20rel%3D%22noopener%20noreferrer%22%3Ehttps%3A%2F%2Fdocs.microsoft.com%2Fen-us%2Fexchange%2Fmail-flow-best-practices%2Fmanage-accepted-domains%2Fmanage-accepted-domains%3C%2FA%3E%3CBR%20%2F%3EOtherwise%20Exchange%20will%20try%20%22internal%22%20delivery%20and%20fail%20unless%20a%20matching%20recipient%20is%20found.%20And%20you%20will%20probably%20also%20need%20to%20configure%20connectors%20to%20ensure%20proper%20mail%20flow%20to%20the%20host-gator%20servers.%3C%2FLINGO-BODY%3E
New Contributor

Hi guys, I hope you are all keeping well and safe.

I have a small challenge with my exchange, I hope to get some help here.

This is my situation.

I have 3 domains D1 (primary domain), D2 and D3 all added on Microsoft exchange under one account. D1 has its mailbox on Exchange whereas D2 and D3 their mailboxes are on host-gator servers.

For pilot test, I licensed several users on D1 since its the primary domain.

Now, when I send email from D1 (primary email) to D3 am getting bounce back.

Another case: When I send from D1 to D2 am not getting bounce back but they are not getting delivered on the other side.

What could be the issue?

3 Replies
You need to set the domain intent for said domains to Internal relay: https://docs.microsoft.com/en-us/exchange/mail-flow-best-practices/manage-accepted-domains/manage-ac...
Otherwise Exchange will try "internal" delivery and fail unless a matching recipient is found. And you will probably also need to configure connectors to ensure proper mail flow to the host-gator servers.

Thanks for your reply @Vasil Michev. I have set the domain intent to "internal relay" and created a connector. Still emails send from 0ffice 365 to my server are not being delivered but from my server to office 365 account are being delivered.

Details are important, otherwise we can only guess...
Also run a message trace, it will give you a clue how a given message is being routed: https://docs.microsoft.com/en-us/microsoft-365/security/office-365-security/message-trace-scc?view=o...