Mozilla does not develop Thunderbird anymore. They have not for 3 or 4 years. Mozilla does not have a staffed help desk to support their 1 existing product, Firefox, so they sure are not going to take calls for Thunderbird. The volunteer group, the Thunderbird Council, has taken over development and support of Thunderbird. Support is provided in this forum only. There are phone numbers out there from scammers using the Thunderbird name but all they do is take your money. Go to the Thunderbird Help menu and click Troubleshooting information. Click Copy to Clipboard. Come back here and paste that info into a reply window.

Thanks -- I tried the "copy to clipboard" procedure as you instructed, but the copied info is too long. I got this prompt when trying to post the reply: "Please keep the length of your content to 10,000 characters or less. It is currently 10,102 characters."

I don't know which parts of that copied material are relevant, so it's hard to edit it for this purpose.

From a MozillaZine page (http://kb.mozillazine.org/Using_Gmail_with_Thunderbird_and_Mozilla_Suite), could the last paragraph of the following section be relevant here? If so, is there a way of undoing Google's "less secure apps setting"? -- Bill

Suddenly can not login in anymore

Gmail routinely blocks logging into a POP account so that they can show you a message. You need to login to webmail using a browser to clear it [3]. Sometimes you can't log in because Gmail thought something suspicious happened, and set a captcha. Thunderbird has no concept of a captcha, you need to login to webmail using a browser to clear it. Similar problems can appear if you use a VPN due to Gmail detecting that your IP address is from a location far from where you normally log in. This can cause security exceptions, and force you to periodically login to google to tell them that the remote login was you.

If you get a popup later on that you have to sign in to the Google account again, and then a "cookies disabled" web page you need to either enable cookies in Tools -> Options -> Privacy -> Web Content or add an exception for Google. [4]

There have been several reports of a working Gmail IMAP account breaking (can't login anymore) due to the allow less secure apps setting changing to disabled. Its not clear why this occurs, but its not something that Thunderbird can change. [5]

You can delete all the printer and font info and then post your info.

Gmail came up with the entire world being less secure than them but that is mostly rubbish. Thunderbird added the OAuth2 authentication type to be used instead of Normal Password just for gmail. This only works for IMAP and SMTP servers so if you use IMAP and not POP make that change to your incoming and outgoing server settings. If you use POP then you have to turn the Less Secure Apps option on at gmail.

Hi again. Just got your message about OAuth2, as follows:

You can delete all the printer and font info and then post your info.

Gmail came up with the entire world being less secure than them but that is mostly rubbish. Thunderbird added the OAuth2 authentication type to be used instead of Normal Password just for gmail. This only works for IMAP and SMTP servers so if you use IMAP and not POP make that change to your incoming and outgoing server settings. If you use POP then you have to turn the Less Secure Apps option on at gmail.

I use IMAP. I adjusted my T-bird server setting from Normal Password to OAuth2 and got through a couple of authorization boxes with Google, and my mail downloaded, but a test message didn't go through. Oy! But then a Google support person came on the line and helped me find the "less secure apps" setting in the Gmail account pages, and switching that off seems to have done the trick. It looks like my T-bird can receive and send mail again. It looks like the problem's solved (at least for now); thanks for your help!

Cheers, Bill