Hi my name is ***** ***** I will be the expert working with you today to help and resolve the problem you have posted.
I am sorry to hear that you are having such trouble. I will try my best to help you out and resolve the problem as quick as possible.
What email service are you using?
how do you access gmail on a web browser on a computer or on a smartphone.
if you are able to login to your account without a problem and you have verified the questions on google then you are all good to go.
Let me know if you have any question.
Clear the browser and reset the settings clear caches and cookies and then try to login.
If you have recently tried to login to the account more than 3 time in that case you will have to restart your internet router and then try to login once you are back online.
If any of the email account has a sign in problem its has to be fixed or else it will block the account. Login to your primary email and login to the email account which you are using it for forwarding if you can login successfully to both the account then there should not be a problem.
let me know when you could be online i will continue further.