Cant access this app on my phone

Well i downloaded this yesterday and it was perfectly fine and then the next day it won't let me get on the app. I tried to log on to my dads phone and it worked. I dont know what to do. I have an iphone 4 and my dad has the original iphone. HELP ME ANYONE

try uninstalling haypi and re installing it. if you need to you might have to reset your phone