iTunes won't let me sign in even though apple id and password are both correct

Every time I open iTunes I am prompted to sign in. I type my info (CORRECTLY) the title bar says accessing iTunes store then I am prompted again to sign in repeatedly and it never works. And yes my computer is connected properly to the internet!

I was looking on another post with this question (and summary above) and finally found the answer. I thought it might be helpful for others to know how I fixed it.

... When you have the iTunes window open, up the top of the computer it has a menu/icon bar which says iTunes on the left and then further toward the right it says 'Account'. I clicked on Account then signed out from this menu dropdown box. Then I signed back in again... and it fixed the issue.

Hope this helps someone else too.