Note As of November 15, 2015, the Zune service has been discontinued. This may cause errors when attempting to stream or download content or update the service.
When you try to use the Zune software, you can’t accept the Zune Terms of Service (TOS).
Typically, this problem happens when the Terms of Service change or when you’ve made a change to your Zune account.
Things to try
First, try the following to solve the problem:
Sign out of all Microsoft account (formerly called Windows Live ID) programs and services before you try to accept the TOS again.
Make sure that you sign in to your Microsoft account correctly. If you forgot your Microsoft account password, go to the Reset your password page. If this is a child account, make sure that it has parental consent.