ActiveStorage and Companion plug-ins?

I am new to Uppy. I have a Rails 6 app with Active Storage. I am running Companion as a standalone Heroku Node.js app.

Uppy uploads files fine from my local machine, but I get the following error when I try to upload files via Dropbox. (I can select files just fine from Dropbox. The error occurs when transfer starts.)

[Error] [Uppy] [21:22:01] – "undefined is not an object (evaluating 'file.response.signed_id') "

The error is coming from index.js and function upload.

I’ll post my code as a gist. I am at a loss – it seems like the response is going amiss.

I found my error. I do have a question though. Do I have to do something to get the Dropbox file to ActiveStorage?