Join the AMA (Ask Me Anything) with the Firefox leadership team to celebrate Firefox 20th anniversary and discuss Firefox’s future on Mozilla Connect. Mark your calendar on Thursday, November 14, 18:00 - 20:00 UTC!

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

Unable to send emails "Login to SMTP server failed"

  • 1 reply
  • 1 has this problem
  • 30 views
  • Last reply by Toad-Hall

more options

I am unable to send emails from my Thunderbird client. This email is hosted through Microsoft 365 (using GoDaddy as a provider). If I log in through the Office 365 Webmail Client, I am able to send a test message to my personal email address and it goes through. This leads me to believe it is strictly a Thunderbird issue. I contacted GoDaddy support and they confirmed that everything is working correctly on their end.

I have attached screenshots of my SMTP settings as well as the error I receive when I try to send an email. The password I use is the same password that lets me login to the Webmail client using Office 365.

I am not sure what is wrong. I have another email address through GoDaddy that uses Microsoft 365 as well and everything works correctly, including sending emails. I have tried cross referencing my settings between the two and everything seems to be in order. I even reset my SMTP password in Office 365 AND in Thunderbird's password manager.

Thank you for your time.

I am unable to send emails from my Thunderbird client. This email is hosted through Microsoft 365 (using GoDaddy as a provider). If I log in through the Office 365 Webmail Client, I am '''able''' to send a test message to my personal email address and it goes through. This leads me to believe it is strictly a Thunderbird issue. I contacted GoDaddy support and they confirmed that everything is working correctly on their end. I have attached screenshots of my SMTP settings as well as the error I receive when I try to send an email. The password I use is the same password that lets me login to the Webmail client using Office 365. I am not sure what is wrong. I have another email address through GoDaddy that uses Microsoft 365 as well and everything works correctly, including sending emails. I have tried cross referencing my settings between the two and everything seems to be in order. I even reset my SMTP password in Office 365 AND in Thunderbird's password manager. Thank you for your time.
Attached screenshots

All Replies (1)

more options

I assume you have two outgoing smtp servers, one for each email address.

The first image shows you using Office365 (Microsoft) -smtp.office365.com (default) But is that the same one as you show in the second image ?

In second image - edit the 'Description' type an A before the 'Office365' and click on OK then look at the account as shown in first image - does it now show AOffice365 ? If no then you are using the wrong smtp server, click on drop down and reselect the correct one that starts with AOffice

Click on OK

Restart Thunderbird.