Remote server returned an error -> 503

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Joined: Tue Aug 29, 2017 6:20 pm

Remote server returned an error -> 503

Postby istvan.pszota » Tue Aug 29, 2017 6:31 pm


I have a strange error: i have a server with MailEnable Standard installed. I have succesfully configured a postoffice and mailboxes. When i'm sending emails from my Hotmail email account to an email address created inside MailEnabe, i receive the folowing error message in Hotmail:

Remote server returned an error -> 503 This mail server requires authentication when attempting to send to a non-local e-mail address. Please check your mail client settings or contact your administrator to verify that the domain or address is defined for this server.

What does this means? I need to authenticate on the server in order to send email to addresses created inside MailEnable? - i guess not
Or the server needs to authenticate in order to forward the received email to the right recipient inside MailEnable?


Any idea would be very helpfull on how can i solve this!

Many thanks in advance!


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Re: Remote server returned an error -> 503

Postby MailEnable-Ian » Tue Sep 05, 2017 1:16 am


Sounds like you have set the SMTP service within MailEnable to require authentication for all connections. Navigate within the MailEnable administration console to: servers > localhost > Services and connectors > SMTP. Right click on the SMTP and select properties. Next navigate to the "Advanced SMTP" tab and ensure that the "Inbound Authentication" setting is to "Do not require authentication".

Ian Margarone
MailEnable Support

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