I watch YouTube on my iPhone, and whenever someone I'm subscribed to uploads, I get an email notification so I can just go to the videos straight from my inbox, as many people do. It used to take me to the YouTube App straight away, but suddenly it switched to opening in Safari. It gives me no option to open the page in YouTube, it used to, but suddenly stopped that as well. I didn't change any settings. How can I get it to open in YouTube by default again?