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:
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!