It could be. -  in very seldom cases - that the iPhone or iPad does block up for some reason or that there are some functions that are not working as they should be. ( ie: Sometimes the devices just doesn't want to connect to the internet although everything is set correctly) 

That's the time to perform a force restart -  this is how you do it on an iPhone:

or on an iPad:

(info) That should resolve the unresponsive devices.  If you still have a function that is not working correctly then now it is probably the time to look for other root causes.

Feel free to create a ticket in our support desk if you need help!