Adding Gmail onto iPhone - it keeps closing!

Earlier today, I tried to add a Gmail account to my iPhone (iPhone 6 Plus). I went to through the same steps as I normally would to add an account but this time I couldn't even get to where I need to type in my Google account details. The minute I tapped the word 'Google', the window pops up showing account.google.com, but then it closes again. I've tried to access this repeatedly, but haven't been able to. Has anyone else had this problem? What's going on, Apple?