SMTP Authentication turned on, but says it is not enabled.

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ngribbs
Posts: 1
Joined: Thu May 27, 2021 9:19 pm

SMTP Authentication turned on, but says it is not enabled.

Post by ngribbs »

Hello,

I am trying to set up a server to work with some in-house applications. I am able to send/receive with other email addresses, but when I am trying to send to our O365 account, we are getting bouncebacks.

Reason: Remote SMTP Server Returned: 550-Please turn on SMTP Authentication in your mail client.
550-(mail.domain.online) [xx.xx.xx.xx]:49224 is not permitted to relay
550 through this server without authentication.

It's weird, I have another server set up that has the exact same settings and we are able to send/receive with no problem.

The only difference is that one is an external IP that we have set up with a secondary internet connection through our VMWare systems, and the one that won't send is using an internal IP. I have the firewall rules set up and DNS is set up correctly. Any help would be appreciated, let me know what other info you may need.

MailEnable-Ian
Site Admin
Posts: 9738
Joined: Mon Mar 22, 2004 4:44 am
Location: Melbourne, Victoria, Australia

Re: SMTP Authentication turned on, but says it is not enabled.

Post by MailEnable-Ian »

Hi,

The bounce back indicates that server requires authentication when sending to it. You may need to allow the MailEnable IP address in Office 365 to relay. Please refer to Office 365 docs.
Regards,

Ian Margarone
MailEnable Support

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