Outlook Error 450 4.7.1 from output server - Microsoft Community

i can't send mail using outlook 2016 professional mail address "*** email address removed privacy ***"

error code output server = "450 4.7.1"
can send , receive mails when using webmail "www.webmail.domain.net".

*** moved outlook.com / email / sending, receiving, , reading email ***

hi gildas,

error 450 4.7.1 indicates exchange server performing reverse lookups identify address sending email. example: suppose want send email example@domain.com, send emails, system stamped ip address of system. now, when the server receives email, verifies first whether email sent through same domain verifying ip address. checks whether ip address pointing same domain, i.e. example@domain.com. if server not able detect sender of email or not able identify hostname, error code 450 4.7.1 client host rejected: cannot find reverse hostname encountered.

we advise contacting recipient's email provider check configuration of mail server , verify whether domain records of dns has been setup or not.

if ip address blacklisted server, find out main cause of blocking. an ip address is marked blacklisted when sending spam link or content. request server remove ip address blacklist.

let know if need else.

Office / Outlook / Other/unknown / Office 2016