I added an new Gmail account to my Mac OS X Mail app in the Dock and it says it's there except I don't get email from that particular account. I opened up the setting for the email and this image is what shows up. When I check the Mail or Notes check box it immediately changes back to blank. How can I fix it?
If you have Two-Step Verification turned on for your Google account, you will need to log onto your Google account and generate an App Specific Password for your MacBook Mail.
You will find it at https://myaccount.google.com
Then go under Sign-in & Security
Scroll down a little bit and then select App Passwords
At the bottom, there is a select an app dropdown along with a my device dropdown.
Follow the instructions to generate a password, then use that password to log into Gmail from your Mail App.