Thunderbird cannot connect to gmail after changing password [FIXED]

0) ALLOW LESS SECURE APPS: Login to gmail using your browser, switch to your google account (top-right round button), go to Sign-in & Security>Connected apps & sites, scroll down until reach Allow less secure apps:OFF and turn it ON (if it's already on, leave as it is);

1) DELETE OLD GMAIL PASSWORD: Launch Thunderbird, select Preferences>Security>Passwords>Saved Passwords, select the gmail account from the list and click Remove; 2) CHANGE GMAIL ACCOUNT SETTINGS: Launch Thunderbird, go to Tools>Account Settings>Server Settings of the gmail account you need to bring back to work, switch Authentication Method from Oauth2 to Normal Password and click OK (when requested by Thunderbird, digit the new gmail password);

3) Scroll down to the end of your account list on the left side of the window until you reach Outgoing Server (SMTP) and select it; 4) Select your gmail address from the list, click Edit, switch the Authentication Method to Normal Password as well and click OK