Notes are not syncronising with iCloud

My Notes on my iPhone is not syncronising with iCloud and my Mac. Whenever I write something on Notes on my iPhone, it doesn't show up on my Mac. I have tried to turn the syncronisation off and start it again with no luck. It used to be syncronising, but suddenly stopped a few weeks ago. On iCloud it says that it's syncronising on both iPhone and Mac. But it's not. Can anyone help? :)