Nano Banana Pro Unsupported file URI type error complete troubleshooting: 5 major causes and a one-time fix
Recently, a customer encountered a very "Google-style" 400 error while using Nano Banana Pro (model ID: gemini-3-pro-image-preview) for image-to-image tasks: { "status_code": 400, "error": { "message": "Unsupported file URI type: {{ $json.imageUrls }}. File URI must be a File API (e.g. https://generativelanguage.googleapis.com/files/<id>), Youtube (e.g. https://www.youtube.com/watch?v=<id>), or HTTPS (e.g. http://path/to/file).), or a valid gURI (e.g. gs://bucket/object",…
