ServiceLocator.Current.GetInstance() returns null, crashing AlloyDemo

Hi all,

I'm currently running through the CMS training content with AlloyDemo, and I'm currently getting a server error for this line:

Object reference not set to an instance of an object.

AdministratorRegistrationPage.cs

Line 57: var res = provider.GetAllUsers(0, 1, out totalUsers);

In addition, I'm getting a similar error for other classes when commenting out Administrator Registration. This happens whenever provider is null, given by the line:

var provider = ServiceLocator.Current.GetInstance<UIUserProvider>();

Does anybody know why ServiceLocator would return null? This happened sort of out of the blue. Everything worked fine on February 6th.

Thank you!