Here is the error:
[400] Error MISSING_REQUIRED_PARAMETER Invalid object
#Upsert1: [merchant_token=D8P315WG03FWV] item variation 6LEDYIMERRSPQZ2RQTVJVA6B is non-stockable and so must also have a composition reference.
But I have it set to stockable?
App ID sq0idp-Yrrrvui1jKbXT1NB5uizpQ
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I’m not seeing that error in the API Logs for that application_id. Are you sure that’s the appID that was used to make the API call? 
It is, but not sure if it would show there? The error message appeared in Make.com. But I figured it out. Tried to delete this post but it wouldn’t let me
Yeah, that’s expected with the Forums.