YouTube – Cannot Upload Opus Audio Only File

I have the following file with no video stream :

$ ffprobe myAudioFile.webm
Input #0, matroska,webm, from 'myAudioFile.webm':
  Metadata:
    ENCODER         : Lavf57.83.100
  Duration: 01:53:19.80, start: 0.000000, bitrate: 25 kb/s
    Stream #0:0(eng): Audio: opus, 48000 Hz, mono, fltp (default)
    Metadata:
      title           : unnamed
      ENCODER         : Lavf57.83.100
      DURATION        : 01:53:19.800000000

When I try to upload it to YouTube, YouTube says :

The video has failed to process. Please make sure you are uploading a
supported file type.

Can you please help me ?