Where did you install Firefox from? Help Mozilla uncover 3rd party websites that offer problematic Firefox installation by taking part in our campaign. There will be swag, and you'll be featured in our blog if you manage to report at least 10 valid reports!

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

Thunderbird

  • 6 replies
  • 1 has this problem
  • 11 views
  • Last reply by storre1508

more options

Hello, since I updated thunderbird to version 78, I have encountered a problem: proxy authentication fails. Thunderbird shows the pop-up window for authentication, the data entered is correct, but it does not authenticate. I have never had any problems before this version. I recently switched from Windows to Mac OS, first Catalina and then Big Sur, with the same version, but the problem persists. I currently have version 78.4.3. Can you help me? Thank you Sebastiano Torre

Hello, since I updated thunderbird to version 78, I have encountered a problem: proxy authentication fails. Thunderbird shows the pop-up window for authentication, the data entered is correct, but it does not authenticate. I have never had any problems before this version. I recently switched from Windows to Mac OS, first Catalina and then Big Sur, with the same version, but the problem persists. I currently have version 78.4.3. Can you help me? Thank you Sebastiano Torre

All Replies (6)

more options

What do you have in Preferences/General/Network & Disk Space/Connection/Settings? Some Mac users have to use something other than the default (Use system proxy settings), e.g. No proxy.

more options

Hi, I checked what you suggested. My settings are: "Use system proxy settings". I tried to set up them manually, but the result has not changed: the pop-up window for authentication keeps coming out.

more options

Do you actually connect through a proxy? If not, did you try setting it to 'no proxy' or 'auto-detect', then restart TB?

more options

Hello, I have tried all combinations of proxy setting. Result: The error message always comes out. I inform you that with other applications I have no authentication problems, whether they use automatic or manual settings.

more options

Can you run OS X in safe mode and see if it makes any difference?

https://support.apple.com/en-ca/guide/mac-help/mh21245/mac

more options

Sorry, but your solution didn't fix my problem and made it worse: thunderbird won't start. I downloaded the latest version (78.5.0) and reinstalled it but nothing: "Application doesn't respond". If you want I could send you the crash report I sent to apple. Thanks