Ah, now I see, you are using the free OCR API key inside Ui.Vision!
If so, what is happening is this: Ui.Vision tries to access the free OCR API endpoint first. If this one is down, it connects to a PRO endpoint. But with your free key, the PRO endpoint returns an error. So this is kind of a bug. It should not access the PRO endpoint, but simply return a “free endpoint down” message.
We do our best to keep the free endpoint up and running, but sometimes it is overloaded. You can see the OCR API status here: https://status.ocr.space/