iOS模拟器不能登录iCloud

I am trying to test the iCloud sync functionality of my app between a (real) device and the simulator, however I can't seem to log into iCloud. When I go to Settings->iCloud and enter my account details, it just gets stuck on 'Verifying'. However if I enter incorrect details, it brings up the invalid password prompt as expected.I am trying to test the iCloud sync functionali