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Windows & Gmail Imap authentication failure

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Hi, 3 weeks ago I suddenly could not log in to my email without errors.

First I get a Google screen "Choose an account" showing the three Gmail accounts I use. I select the first one.

"Mozilla Thunderbird wants to access your Google Account". This refers to calendars. I take the Allow option.

Then I get the message "Warning: Potential Security Risk Ahead

Thunderbird detected a potential security threat and did not continue to localhost. If you visit this site, attackers could try to steal information like your passwords, emails, or credit card details."

When I close this window I get another Google screen .

"Mozilla Thunderbird wants to access your Google Account". This refers to i) mail, ii) contacts, and iii) calendars. I take the Allow option.

Then I get the same message message "Warning: Potential Security Risk Ahead

Thunderbird detected a potential security threat and did not continue to localhost. If you visit this site, attackers could try to steal information like your passwords, emails, or credit card details."

This process cycles through the other two emails. Then I get and authentication failure message.

I have seen hints that this might be a certificate issue but I have tried in vain to find certificates stored in Thunderbird.

Any help approeciated.

Thanks

PaulM

Hi, 3 weeks ago I suddenly could not log in to my email without errors. First I get a Google screen "Choose an account" showing the three Gmail accounts I use. I select the first one. "Mozilla Thunderbird wants to access your Google Account". This refers to calendars. I take the Allow option. Then I get the message "Warning: Potential Security Risk Ahead Thunderbird detected a potential security threat and did not continue to localhost. If you visit this site, attackers could try to steal information like your passwords, emails, or credit card details." When I close this window I get another Google screen . "Mozilla Thunderbird wants to access your Google Account". This refers to i) mail, ii) contacts, and iii) calendars. I take the Allow option. Then I get the same message message "Warning: Potential Security Risk Ahead Thunderbird detected a potential security threat and did not continue to localhost. If you visit this site, attackers could try to steal information like your passwords, emails, or credit card details." This process cycles through the other two emails. Then I get and authentication failure message. I have seen hints that this might be a certificate issue but I have tried in vain to find certificates stored in Thunderbird. Any help approeciated. Thanks PaulM

Chosen solution

Thanks Chris, I think it is solved now. I started in safe mode as described. When I started up Thunderbird it went through the process of logging into the different email accounts - even though I had deleted the saved passwords it found them from somewhere. And now, back in normal windows operation it starts OK. Miraculous!

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All Replies (7)

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Are you running a local web server, or is any other application running on your computer already using localhost? Anti-virus/security software tend do this.

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Thanks Chris for your response. I 'm running standard Windows 11 and am not aware of a local web server. I am using Norton anti-virus. I have tried switching this off and restarting Thunderbird, it makes no difference. I also tried restarting windows in safe mode, this did not seem to help either but I am going to try this again.

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Can you post a screenshot of the warning you get? https://support.mozilla.org/kb/how-do-i-create-screenshot-my-problem

I am using Norton anti-virus. I have tried switching this off and restarting Thunderbird, it makes no difference.

Try to start Windows 10 in safe mode with networking enabled.

Still in Windows safe mode, start Thunderbird in safe mode. Does the problem go away?

Windows safe mode disables anti-virus software. This is a troubleshooting step, not a solution.

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Here's the warning message. I'm not sure why it starts with the calendar. Nothing different from what is mentioned above. After several of these for each account I get a second message which I'll try to pick up.

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As I mentioned I am using Windows 11. Probably you mean safemode for Windows 11? I'll trry that again later. Thanks

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Chosen Solution

Thanks Chris, I think it is solved now. I started in safe mode as described. When I started up Thunderbird it went through the process of logging into the different email accounts - even though I had deleted the saved passwords it found them from somewhere. And now, back in normal windows operation it starts OK. Miraculous!

Helpful?

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christ1 said

Are you running a local web server, or is any other application running on your computer already using localhost? Anti-virus/security software tend do this.

That was my problem - turns out I was tinkering with nginx a few years ago, and never got around to uninstalling it. Once I did, Thunderbird started behaving again. (I'm running a Linux system).

I'm puzzled as to why Thunderbird started trying to connect to https://localhost in the first place (and on the default port; if it was connecting to some internal service, I'd expect it to choose some secret port). What's it up to?

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