Split from this thread.
I have a similar issue but the resolution here doesnt seem to be the able to resolve it. I just created an office 365 mail and i can receive emails from any mailbox. Sending out is the problem. I get this error for every email I send from there. The email was created for Business. (Custom domain). I wonder if it is the setup that caused the issue, not sure. Below is an extract of the NDR i get everytime an email is sent from the mailbox.
Diagnostic information for administrators:
Generating server: HE**94.EURP190.PROD.OUTLOOK.COM
Remote Server returned '550 5.7.708 Service unavailable. Access denied, traffic not accepted from this IP. For more information please go to http://go.microsoft.com/fwlink/?LinkId=526653 AS(8561) [HE**43.EURP190.PROD.OUTLOOK.COM]'
Original message headers:
Received: from HE**94.EURP190.PROD.OUTLOOK.COM ([f***a]) by HE**94.EURP190.PROD.OUTLOOK.COM ([f**4]) with mapi id 1**5; Sat, 9 Jun 2018 05:38:30 +0000 MIME-Version: 1.0 Content-Type: text/plain Date: Sat, 9 Jun 2018 05:38:30 +0000 Message-ID: <HE***94.EURP190.PROD.OUTLOOK.COM> Subject: Re: Email Facility