Resize video while live streaming with ffmpeg
You wanted to resize your video (-vf scale="480:-1"), and at the same time you wanted don't to use a video codec for encoding such resized video (-vcodec copy).

It's impssible — video codec copy means no decoding, no encoding, no filtering - simply copying without any change. It is not a real codec.

Try omitting -vcodec copy to enable FFmpeg to choose an appropriate codec.