unable to sign into iTunes account in itunes

[mrgreeneyes]

Hey

i seem to have been logged out, and i cannot sign back into my account in iTunes.
when i click on account, and the drop down menu comes down, and i click on sign in, nothing happens, i don't get any pop up window.

i have tried everything, uninstall iTunes, and re-install it. clear the cache, cleared safari cache.

and still nothing works.

i have the newest iTunes 12.5.1.23
and the latest safari 10.0

any help would be amazing.

thanks