It will not let me sign into iTunes and keeps opening new tabs

If you are seeing tabs you are apparently in a browser, and that is not how you access iTunes. Go into the iTunes (or Music) app.

Hi hudson50,

Thank you for posting in the Apple Support Communities! It's great to be able to use the iTunes Store on your Mac. I'll be glad to see how I can assist, and I'd like to start by getting a little information.

What exactly is happening when you say it won't let you sign in? If you're getting an error message, what does it say?

You mentioned opening tabs; are you referring to a separate issue with tabs opening in another app? Be sure to provide as much detail as possible.

Also, which macOS or OS X version are you using?

As a starting point, give the steps here a try to see if they're helpful for the iTunes Store issue: If you can't connect to the App Store, iTunes Store, or other Apple services

Please reply back with an update on the issue if needed, and have a great day.