I currently have a hybrid environment with Office 365 and Exchange 2013 where all mailboxes reside in 365 but Exchange is used for SMTP relay of various applications/devices. Up until now everything that has had to utilize SMTP relay has been on our internal network so I setup the receive connectors on the CAS servers but now we need some non-domain joined application servers in azure to be able to SMTP relay and I can't seem to get it to work. I created a receive connector on the edge server for relay, added the necessary remoteIPRanges for the application servers but when testing with a simple send-mailmessage command in powershell I receive the following error "Send-MailMessage : Unable to connect to the remote server".
Is it because it only has the Hub Transport role installed or possibly because the permission group is only set to AnonymousUsers rather than AnonymousUsers and Custom like my CAS servers are? Any help would be greatly appreciated.