I have found an issue. A student brought an IPhone and said she could get into Google Classroom and see the assignments, but when she clicked it, she needed access. The problem was that she was using the Chrome browser for the assignment not the associated Google App. The browser she was using on her phone was signed into her personal account and not her school account. When I change the account on the browser, by clicking the user icon at the top and changing the account, everything worked great.
