My son uses the Sky Sports app on his desktop PC and has been having a lot of problems with it. I have had to uninstall and reinstall it a number of times till we got it to work.
I am afraid "Unexpected Error" on your iPad does not help us much, and I have done a search on the message and it seems a lot of people have had this error on their iPads over the last few months.
I cant see any obvious fix so can only suggest very general things.
Make sure you have the iPad operating system iOS up to its latest level.
Then try turning your iPad fully off and on again and try the app again.
If that does not fix it then UNINSTALL the app, then turn the iPad off then back on again, then REINSTALL the app.
I know they are all very general things but it is difficult to give much help with such a vague error message