Issues getting emails from Microsoft

[luisedofon]

Hi guys, recently I got a VPS and have installed HestiaCP, this is for a project of the company I work for, we were looking to reduce servers cost and so, I have a supervisor here that says that he gets emails from someone that is related to Microsoft encrypted message, the issue is that he supposed to get an OTP code from the microsoft thing from email [email protected], but is not getting in even on spam, I have already whitelist this email on spamassassin config but still not, I have research on Forum I saw on a topic @sahsanu mentioned to check /var/log/exim4/rejectlog. So I did it and test to send pass code to have fresh records and I got this:

2024-11-04 21:59:44 H=mail-bn8nam12on2126.outbound.protection.outlook.com (NAM12-BN8-obe.outbound.protection.outlook.com) [40.107.237.126] sender verify fail for [email protected]: all relevant MX records point to non-existent hosts
2024-11-04 21:59:44 H=mail-bn8nam12on2126.outbound.protection.outlook.com (NAM12-BN8-obe.outbound.protection.outlook.com) [40.107.237.126] X=TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_128_GCM:128 CV=no SNI=mail.css-cr.com F=[email protected] rejected RCPT [email protected]: Sender verify failed
2024-11-04 22:08:38 H=mail-bn1nam02on2109.outbound.protection.outlook.com (NAM02-BN1-obe.outbound.protection.outlook.com) [40.107.212.109] sender verify fail for [email protected]: all relevant MX records point to non-existent hosts
2024-11-04 22:08:38 H=mail-bn1nam02on2109.outbound.protection.outlook.com (NAM02-BN1-obe.outbound.protection.outlook.com) [40.107.212.109] X=TLS1.2:ECDHE_SECP256R1__RSA_SHA256__AES_128_GCM:128 CV=no SNI=mail.css-cr.com F=[email protected] rejected RCPT [email protected]: Sender verify failed

I hide our css-cr.com email just in case, hope someone can help me

[sahsanu]

Hi @luisedofon

@luisedofon

sender verify fail for [email protected]: all relevant MX records point to non-existent hosts

The message is clear, the domain messaging.microsoft.com has an MX record defined:

$ dig messaging.microsoft.com mx +noall +ans
messaging.microsoft.com. 2636   IN      MX      10 messaging-microsoft-com.mail.protection.outlook.com.

But host messaging-microsoft-com.mail.protection.outlook.com doesn’t resolve to an IP.

$ dig messaging-microsoft-com.mail.protection.outlook.com a +noall +ans
$ dig messaging-microsoft-com.mail.protection.outlook.com aaaa +noall +ans

And obviously, that’s wrong, that is a Microsoft issue.

Anyway, if those messages are importat to you, edit /etc/exim4/exim4.conf.template and in block acl_check_rcpt add this line

  accept senders        = *@messaging.microsoft.com

Before this one:

  require verify        = sender

In context:

[...]
  deny    message       = Restricted characters in address
          domains       = !+local_domains
          local_parts   = ^[./|] : ^.*[@%!] : ^.*/\\.\\./

  accept senders        = *@messaging.microsoft.com

  require verify        = sender

  accept  hosts         = +relay_from_hosts
          control       = submission

  accept  authenticated = *
          control       = submission/domain=
[...]

Once modified, restart exim4:

systemctl restart exim4

[luisedofon]

Thank you so much @sahsanu , I already modify it, will test it tomorrow at work

Edit: Nevermind hahaha, just test it and it worked, I’m on a bar at work VPN haha, thanks a lot for the help @sahsanu, thank you so much, really appreciated