This process will open the Mozilla Thunderbird Email Client in a protective mode. If Mozilla Thunderbird is not running, then start the app at the same moment and hold the SHIFT key of your computer’s keyboard.

Starting Mozilla Thunderbird Email in a Safe Mode Look the screen for “Allow Mozzila Thunderbird to do this” message and tap on Allow optionĬheck, if Mozilla Thunderbird Authentication Failing Error is resolved or not.Restart the Mozilla Thunderbird Email Account, and once it is started, you will be asked to enter the password of your email account. Search to Outgoing Server and choose OAuth2 Authentication Method.Go to your email account, choose Server Settings option on the left panel and then select Oauth2 from the Authentication Method with drop-down menu. Search Menu to the main window of the Mozilla Thunderbird Email.Now, choose the Saved Passwords option, and it will remove the previously saved passwords in Mozilla Thunderbird Email Account.Open the Mozilla Thunderbird and go to its primary interfaces and search to the Preferences window, and click the Security option at the top of the screen.If you have saved the old passwords in Mozilla Thunderbird Email account, then you need to remove these soon to resolve this Authentication Failure Error.What are the Troubleshooting Steps to Fix Thunderbird Authentication Failure Error?įollowing these steps will give a meaningful result in washing-off this error from your Mozilla Thunderbird email account. If you are encountering the “ Mozilla Thunderbird Authentication Failure” message in the Mozilla Thunderbird Email account, then you should follow the given instructions to resolve this error soon.

Mozilla thunderbird login failed