ASP.NET Identity Provider SignInManager Keeps Returning Failure

If username != email:

ApplicationUser signedUser = UserManager.FindByEmail(model.Email);
var result = await SignInManager.PasswordSignInAsync(signedUser.UserName, model.Password, model.RememberMe, shouldLockout: false);

SignInManager.PasswordSignIn works off of user name, you should double check that the user name is the same as the email you are passing in.