Fix push on iPhone

My daughter wanted me to use WhatsApp, as it would save her SMS's. I think WhatsApp is supposed to use push notifications when a message is sent to me, but i did not get those push messages. In an attempt to test what was the cause and solution, i first installed iPushTest. The 'Timed Push Test' did not work, despite me doing everything the help-file told me in case of push notifications not working. Then i tried Push Doctor, which i found through this thread. And that made the notifications of iPushTest appear.