Getting familiar with Einstein Vision by doing the tutorial at https://metamind.readme.io/v1/docs

Everything fine until I try to predict against the demo image and I just get:

{"message":"Forbidden!"}

That's no fun. I've checked & refreshed my token; the modelid is correct; I can access the sample image...

Anyone have insight on the specific meaning of this message?

curl -X POST -H "Authorization: Bearer a48a051c9d1110099999999914b42042df96f" -H "Cache-Control: no-cache" -H "Content-Type: multipart/form-data" -F "sampleLocation=http://metamind.io/images/546212389.jpg" -F "modelId=1101631" https://api.metamind.io/v1/vision/predict