I accidentally signed up for 2 step verification and now I cannot get into my Gmail account on my MacBook using Mail.app. I don't have a phone where I can access emails so this is all confusing.
Here it is explained how to turn off 2-step verification. If you don't have a mobile app or a mobile phone for verification, you should have received temporary codes. If you did not save them, well, then just follow the link below the login box where it says "Can't access your account?".
If you don't have phone, you can use the backup codes if you noted it already, else select
Can't access your account ?
Select I can't access my phone and backup code
Fill the form and wait for 2-3 days