I spent a while building a service that publishes to Instagram on a schedule. Most of that time did not go into the interesting parts. It went into errors whose message points nowhere near the actual cause. Here is the list I wish I had found on day one. 1. Publishing is two calls, and the first one publishes nothing You do not post a photo. You create a media container , then you publish that container: POST /{ig-user-id}/media -> returns a creation_id PO...