2-step verification is a security of your Gmail account, via which you are notified with the device name and time while you are login your email id in any other device. If you are not able to activate 2-step verification for the Gmail account on its app, then you should confirm you are using an active account and provide the correct user’s credential and the mobile number or alternate email id. If you still unable to do it, then Contact Gmail by Phone to resolve it. https://www.numbersupportcustomerservice.com/gmail-customer-service/