Upcoming Gmail changes
Google is turning off the “allow less secure apps” option at the end of May 2022.
Users with Outlook 2016 (retail version), 2019, 2021, and 365 won't have a problem when Less Secure Apps is disabled. They can connect to Gmail accounts (using IMAP) with Allow less secure apps turned off. Gmail users with older versions of Outlook who want to continue to use Outlook will have two options: upgrade to new version of Office or enable two step verification on their account and use an app password.
At this time, adding a Gmail account to Outlook as POP will require the user to enable two-step verification and use an app password to log in. Newer versions of Outlook will need to use app passwords with POP accounts too.
To enable two-step verification and get an app password, log into your Google account and open the Security settings.
It is highly recommended that you use two step verification even if you are using a supported version of Outlook!
If you are unable to enable two-step verification and upgrading Office is not in the cards, you’ll need to use a different email client or use Gmail.com. (I recommend eM client as a good Outlook replacement.)
Task 'firstname.lastname@example.org - Receiving' reported error (0x800CCC92): 'Your email server rejected your login. Verify your username and password for this account in Account Settings. The server responded: -ERR [AUTH] Username and password not accepted."
If you have the account added as POP and receive this error, you need to use an app password to sign in. If you do not have two-step verification enabled, you will need to enable it to create an app password.
Older versions of Outlook can't connect to Gmail servers unless you also enable two-factor authorization then use an app password in Outlook. (The app password is a one-time use password that can be voided if you suspect it is compromised, without affecting your “real” password.)
To check or change your settings, sign in to Gmail then open your Google account settings.
If you enable two-factor authentication, you'll create new app passwords at App passwords. Gmail allows you to revoke individual app passwords, which you can do by clicking the trash can icon to the right of the device name.
In my experience with Gmail, their implementation of two-factor authorization is not annoying at all and retains the authorization. It doesn't request re-authorization often, which makes using an app password fairly painless. If you use public hotspots, you should enable two-factor.
Add an App Password video
Please note: the email address shown in the video is used only for testing and screenshots. I will not reply to email sent to it.
While the YouTube video below was recording using Outlook from Office 365, the steps are basically the same for all versions. I have a recording made using Outlook 2007 here.