Issues sending mail to mms.att.net troubleshooting RRS feed

  • Question

  • Up until this past Monday at noon we can't seem to send email to mms.att.net.  We use Nagios to monitor our network and notifications are setup to send to our cell phone's email addresses via our Exchange 2016 on prem box.  All of the other carriers are working without issue.  When I run a Test-Mailflow to my cell phone's address it shows as failure but it also shows as failure to my gmail account.  I can send a message to my cell phone via powershell

    Send-MailMessage -To "phonenumber@mmst.att.net" -From "Myemail@contoso.com" -Subject "Test email from Contoso" -SmtpServer "FQDN of my MX box"

    I'm not getting an NDRs or errors on the server specific to a failed delivery.  I've added my email to the pager group within Nagios and the emails come in to that inbox just fine.  I've sent an email to a postmaster email I found for AT&T to see if our IP is being blocked however I don't see it on any of the blacklists when I run a check on mxtoolbox.  Does anyone have anything else I can do to troubleshoot this?  

    Thursday, October 18, 2018 1:13 PM


All replies

  • After doing some digging I found out ATT is blocking us from sending to mms addresses.  
    Friday, October 19, 2018 2:58 AM
  • Hi IndyBeerGuy,

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    Friday, October 19, 2018 4:19 AM