Why can't I access the app after installing?

I have gone through all the steps to install the app and I believe I have done it properly. However, it gives me an HTTP Error 500 when I tried using the app. What could be wrong?

There are a few possible reasons for this issue. The most common issue is that the app currently doesn't support your default currency. This issue only affects accessing the app as the currency conversion on your store will still work properly. Changing the store's default currency will resolve the access issue. Our development team is currently working on support for additional currencies.