I have no idea how to buy mine coins!

So i was going to buy skywars rank in cubecraft and when i went to purchase the minecoins it says ‘cannot connect to the app store myabe check your internet connection’ so i went to settings and conneted to the wifi at full bars then i went back in and it
said ‘soemone has already started a purchase on this account would you like to continue’ so i click continue and it says the same thing that it cannot connect to app store how can i fix this would restoring purchases help? If so please tell me how to restore
purchases

:)