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osTicket v1.10 (stable) and Maintenance Release v1.9.15 are now available! Go get it now

[resolved] SMTP problem - Client host rejected & cannot use authentication

Hi - The system log is showing errors for email sending with the following text:
"Unable to email via SMTP::587 [] Failed to add recipient: [SMTP: Invalid response code received from server (code: 554, response: 5.7.1 : Client host rejected: Access denied)] "

I thought the issue might be not using authentication in the SMTP settings for the email address, but when I try to set Authentication Required to 'Yes' and save, I get the error "Unable to log in. Check SMTP settings." - The thing is, the SMTP settings I'm using are the same as those I use in Thunderbird, which has no problem sending.

Any help would be appreciated


  • version of osTicket?
    actual settings you are using?
    have you tried prefix of ssl:\\ in the host name?
    Do you have SElinux, mod_security, or another firewall software on the web server -or- a firewall on the mail server that might be preventing the connection?
  • Hi - sorry for the delayed response. It seems I have resolved the SMTP issue with my hosting provider. Thanks for your help.
  • Very welcome. HAve a great day!
This discussion has been closed.