Seems to come from an issue registering the Speech to Text callback in the toolchain.

The call to register fails with an error 406. It could be due to a concurrency issue where the speechtotext web action is not yet exposed by OpenWhisk when we try to call it during registration.

A re-run of the pipeline usually solves the issue.

{"code":400,"code_description":"Bad Request","error":"unable to register callback url 'https://openwhisk.ng.bluemix.net/api/v1/experimental/web/user_space/vision/speechtotext.http', callback server responded with status code 406"}