Having trouble with Get content from CDN to Update my game's version in Unreal Engine 4

Hi! I'm using Play Fab for an educational game on Unreal Engine 4 and I'm trying to release my game soon, then keep updating constantly with new material. But It has been hard to write the Blue Prints with the documentation examples.

Can someone could help me to figure out how to write my BP please? any information or idea it's going to help a lot.

Thanks and best regards!

Here is the settings that I started, I set two debug strings just to see if GetContentDownloadUrl is working, but it always print the Error String
getfiles.png