macbook air early 2014

No, ok I try to tell what I do:

I add a new account e chose Gmail, so I sign my Gmail address and then , when he asked to me the PW of the address I sign it.

At this point, in he left corner, star the loading icon for one second and he show what service I won't.

So, at this moment I chose Email service.

Now, on the bottom bar I have only the possibility to chose cancel button and the Next/Finisch button isn't possible to push.

I have other 2 email addresses but I have problems only with Gmail.

Is possible Mail have problems for the new system of double recognized system?

I don't why?

I try to add a email addres but when I arrive to choose the service (mail, note, Msg... ecc) he doesn't allow me to finish the installation.

At this point I don't know what I have to do.

Ok I try to do it

Thanks