Cant purchase procreate

I just bought the iPad mini 5th generation so I could have procreate, but its not allowing me to purchase the app. When I try in the apple store, it will ask me to put in my password, load for a bit and say done, but when the apple store loads its still asking me to purchase the app. I tried sending it as a gift to my email, but it wasn't able to connect with the app store. My software version is 13.6. Any suggestions?