After days of trial and error, I’ve found that the GenAI SDK keeps freezing up when generating 4K images with the Nano Banana Pro model.

Either my code times out and terminates after 30 minutes, or it consistently throws the error shown below. What’s worse, the SDK doesn’t even provide an asynchronous processing mechanism to resolve such long-wait issues. In all the tests over these days, generating a 1K image takes about 15–20 seconds and a 2K video roughly one minute—yet generating a 4K video has never succeeded at all!

Is this a known issue? I haven’t seen anyone complain about this (yet).

google.genai.errors.ServerError: 503 UNAVAILABLE. {'error': {'code': 503, 'message': 'The model is overloaded. Please try again later.', 'status': 'UNAVAILABLE'}}

I have tried for many days, and I paid for it.