I have followed the online Exchange 2013 jump start to configure my Exchange server.  Due to electrical power problems in our country (South Africa) we decided to install a dedicated server with MS Exchange 2013 in a data center that guaranteed up-time.

The server now accepts mails for our domain.  We can mail other recipients in our domain without a problem.  When we try to mail an external recipient we get a no relay allowed error.

I have registered an authoritative Accepted domain as instructed.

If one uses the OWA to send mails it works fine as well.

How do I allow for relaying of mail from "internal" addresses only.

Thanks

Hello

set-remotedomain * -AutoForwardEnabled $true not help?

Hi,

According to your question, I notice that OWA works fine. It indicate that Exchange server works fine.

I assume Site B is new datacenter and Site A is original datacenter, please ensure user in site A or site B works well with OWA.
Also, try above suggestion for further troubleshooting.