On May 30, You may lose access to apps that are using less secure sign-in technology!
To help keep your account secure, Google will no longer support the use of third party apps or devices which ask you to sign in to your Google account with only your username and password. Instead, you’ll need to sign in using Sign in with Google or other more secure technologies like OAuth 2.0
What do you need to do?
Email software, like Outlook 2016 or earlier, has less secure access to your Gmail. Switch to Outlook 2019 or newer, or any other email software where you can sign in using Sign in with Google.