We're calling on all EU-based Mozillians with iOS or iPadOS devices to help us monitor Apple’s new browser choice screens. Join the effort to hold Big Tech to account!

This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Msg send with Thunderbird - but is never delivered - SMTP protocol issue? As outlook works fine.

  • 1 nzaghachinzaghachi
  • 1 nwere nsogbu anwere nsogbu a
  • 1 view
  • Nzaghachi ikpeazụ nke Matt

more options

Hi All,

Fighting with my providers ( mydomain.com / Telus )

Identical setup in both TB and Outlook 2013. Msgs coming in fine. When sending a msg in TB - TB tells me it is sent and puts it in the Sent folder However msg never arrives...

Same msg send from outlook arrives no problem.

POP / SMTP on 587 setup Can see traffic on router using packet sniffer when sending eMail

Worked for years stopped working 2-3 weeks ago. Sometimes works for a couple hours...

Same issue when using other provider (Telus) so problem not tied to MyDomain alone...

Updated to latest version of TB 31.1.1 - no fix.


TB 31.1.1 on 2 other computers with other eMail address (same providers) One works, one does not... receiving eMail is never an issue...

Very weird... looking for hints, clues to research this to proof where the problem sits.


Regards

Peter

Hi All, Fighting with my providers ( mydomain.com / Telus ) Identical setup in both TB and Outlook 2013. Msgs coming in fine. When sending a msg in TB - TB tells me it is sent and puts it in the Sent folder However msg never arrives... Same msg send from outlook arrives no problem. POP / SMTP on 587 setup Can see traffic on router using packet sniffer when sending eMail Worked for years stopped working 2-3 weeks ago. Sometimes works for a couple hours... Same issue when using other provider (Telus) so problem not tied to MyDomain alone... Updated to latest version of TB 31.1.1 - no fix. TB 31.1.1 on 2 other computers with other eMail address (same providers) One works, one does not... receiving eMail is never an issue... Very weird... looking for hints, clues to research this to proof where the problem sits. Regards Peter

All Replies (1)

more options

My guess is we are seeing one of two things.

Your IP address being blacklisted for SPAM a check at spamhaus will answer

that one.

Alternatively some idiot in the big providers has found a new way to mess with legitimate mail in the name of SPAM control.

A common difference between Outlook and Thunderbird is the inclusion of the reply-to: header. Check your account setup that it is blank (right click the account folder and select settings) This was a source of friction when Yahoo out of the blue started marking all mail with it as spam and just as suddenly stopped (No announcement from Yahoo support for either event)

Do you have a signature on these mails?