seems trying to retrieve data from google sheets by a keyword catpured in capture block, and there’s no keys in Google sheets and returns nothing.
Two things to check.
make sure if a keyword in capture block is captured correctly. This is the main reason I think. In Voiceflow’s test, capture block just capture what user said as slot, even if its slot type is not matched with what user said. In ADC, Alexa will capture what user said with checking if it is valid for slot type. If it is not valid, return nothing. (actually returns fallback intent, but capture block cannot receive it and a variable will be just null, I think).
If retriving data from Google sheets with a key as a condition and there’s no data matched, it will not go to failure path. Failure path is for connecting errors to google sheets, not for no data. so you should check variables mapped from result using if block after google sheets block.
are you using Stream block to play audio? Stream block use Alexa’s feature called AudioPlayer, which is built-in Audio Player in Echo devices and test simulator in Alexa Developer Console does not support AudioPlayer. AudioPlayer skill can be tested on real Echo devices only.