A 429 error is often returned when the provider actually performing the generation returns a "busy" status. In some cases, retrying may allow the generation to proceed.
There are two patterns: the censorship AI blocks the request at the entry point, or the generation model itself refuses the request.
In the latter case, it may pass depending on the retry seed, but this is not recommended as it often leads to the story being continuously "nerfed" thereafter.
Please change your settings or switch to a model with more lenient censorship.
Connection error when specifying certain providers other than OpenRouter
For providers such as Google AI Studio and Sakura AI Engine, it appears that server-side CORS settings prevent access from web applications.
Regarding Google, this may be because it is accessed via the OpenAI SDK.