Hi everyone. I’m a complete beginner with Google Cloud, so please go easy on me and explain things simply if you can. I’m learning as I go and may be using the wrong terms.

What I’m doing

I signed up for the $300 free trial credit and made a Vertex AI API key . I use it to call Gemini models from code with a simple request to https://aiplatform.googleapis.com/v1/publishers/google/models/{model}:generateContent .

What works and what doesn’t

✅ Works: gemini-3.8-flash , gemini-3.5-flash , gemini-3.5-flash-lite , gemini-3.1-pro-preview , gemini-3-flash-preview and gemini-2.5-flash-image .

❌ gemini-4-argon gives me this error: 404 NOT_FOUND: Publisher model ... was not found or your project does not have access to it .

On my console’s Welcome page, Gemini 4 Argon is listed as “New”, so I thought I could use it.

What I’m confused about

Why can’t I use Argon if it’s listed in the console? Is it blocked on free-trial projects, or do I need to turn something on or request access?…