Sorry to see that. I tried the prompt after translating "the girl winked turned away, spreading her hair" and got the same error. I removed the "winked" word from the prompt and able to generate the video.
I have a few questions to help track down this problem.
If you have a personal plan, have you subscribed to a premium Firefly plan? A premium Firefly plan is needed to generate video for people on personal plans. If you did subscribe to a premium Firefly plan, which plan did you subscribe to? (See plans listed here.) Or are you on an enterprise plan?
Can you generate Firefly video without a keyframe?
Is your keyframe aspect ratio exactly 16:9?
Please tell us what OS and browser you are using along with their version numbers.