@Leeann The purpose of using connected accounts for auth is so that we don't log the API keys are anything like that in plain text. However, taking a look at the set up it looks identical to the manual test you did where you did copy the credentials in plain text.
If you provide the API documentation for this endpoint I can take a look and see if I can replicate something locally and figure out what is going on. It could easily be an issue with the way that files are treated on the generic Wrk Action. We may need to make a specific Wrk Action for Axo so that we can guarantee that files are treated correctly for this API.