are you aware of the generic issue re: bubble connector AND POST reqs having complex query expressions after the path ? API connector Stripe.checkout.sessions init error - #6 by rowntreerob is an example . There are alot more examples of workarounds re: http(s) posts such as yours via the api connector.
following that logic you could try the translation from the good Curl expression of the Post to the bubble workaround using the json body form property as kludge-wrapper for the query string used in the curl …
> --data 'type=upload&public_id==sample&eager=w_400,h_400,c_crop,g_face|w_660,h_400,c_pad,b_blue×tamp=173719931&api_key=436464676&signature=a788d68f86a6f868af'
