If you had an App Password and now no longer works, it is most likely you changed your email address password or you turned off 2-factor-authentication; thus Google removes the password for security reasons. To resolve the issue, make sure you are logged in into the correct Gmail Account on your default Internet browser, and click the following link

https://myaccount.google.com/apppasswords  

then enter the name of the app, for example: LimoWiz, then copy the paste the generated into LimoWiz password field on the Email Account tab and click the Test Account Settings button. Do NOT type the App Password manually; just copy and paste!  If 2-Factor Authentication is off, it must be turned on; read instructions below.

Never created an App Password? Here are the steps to create an App Password.

1. Turn on Two Step Verification on your Gmail account.
   
2. Create an App Password for LimoWiz.
3. Copy and Paste the new password into LimoWiz email settings.
4. Save the App Password into a safe location.

Important note:
If you have already created an App Password and you later change your email address password, Google erases App Passwords with no prior notice. Therefore, applications that use an app password will not send emails, so you will have to create a new password as per the instructions below.

Here is a walk-through:

Click the Google Apps icon on top right of your Gmail account, and select Account.

Then click Security then click 2-Step Verification. See Red arrows.

NOTE: If 2-step verification is already turned on, click here: App Passwords.

If you step 2-Verification is not visible in your account,  visit https://myaccount.google.com/apppasswords, then follow the steps at App Passwords. below.

FINALLY!

WIth mouse, the highlight the App Password and paste into the password field in the LimoWiz Settings:

See Gmail Account Setup in LimoWiz article at: https://limowiz.com/faqview?FAQ_ID=59