Error in call to API function "files/list_folder": This function requires its argument in the HTTP r

The /2/files/download and /2/files/list_folder endpoints use different formats, so those wold need to be implemented differently and so aren't a good comparison. The /2/files/list_folder endpoint is an RPC style endpoint, meaning that it requires the parameters JSON in the request body.

The error message you received indicates that the API did not receive the parameters in the request body for that API call.

It looks like you have the data for the parameters in "params", so you'll need to make sure that's getting properly sent in the request body. I can't offer help for third party network clients themselves, as they're not made by Dropbox, so I recommend referring to the documentation for your client for information on how to configure it.

Also, I notice from the partial screenshots you shared that the two scenarios you have for /2/files/list_folder do not seem to be configured the same way: the working one has "content-type" set in "headers", and the non-working one has "content-type" set in "attribs". In addition to sending the parameters in the request body, make sure you are correctly setting the "content-type" header to "application/json".