cannot connect to iTunes Store on iPad 1st generation

Start here:

If you can't connect to the App Store, iTunes Store, or other Apple services - Apple Support

noting Item 3 regarding system software. A 1st Gen iPad can run no higher than iOS 5.x; current is v18. That could be the source of your issue.

If you get a login attempt requiring a six-digit verification code, you cannot enter it normally on an older iPad. If your user login password is "myoldipad," and a trusted device give you a six-digit authentication code like "123456," you append the code to the end of your password, making it "myoldipad123456"

I am sorry to say I believe they have disabled the access for these legacy devices. Just this afternoon I grabbed my 1st gen iPad and tried to go re-download an app I had uninstalled and wanted to see if I could try it out again and sure thing, the iTunes app, iBooks, and music stores are giving this error.

I think it's over. But with that said, it still streams movies and tv like a champ from my "TV" server (I will never be happy with renaming it "TV") If anyone else has a solution, I'd love to hear it.