Error in call to API function "sharing/list_folders"

[Cross-linking for reference: https://stackoverflow.com/questions/45937861/error-in-call-to-api-function-sharing-list-folders ]

This error message indicates that the request body, which is supposed to contain the API call parameters as JSON, could not be successfully read by the Dropbox API as JSON.

That error looks correct in this case, as you're supplying form URL encoded parameters instead of JSON. The JSON would instead look like:

"{"limit": 100,"actions": []}"