Time captions to the voice-over listens to the audio in your video. It found no spoken words, for example because the track is music only. The writing request was not counted.
You may also see:
"Transcription failed. Please try again."
"Audio up to 25 MB can be transcribed."
"Choose a voice-over first."
What to do
Check the audio has clear speech.
For music-only tracks, type your captions and tap Spread across the video.
For long audio, use a file under 25 MB.