A muted video, a video with the audio replaced by silence, or a post taken down entirely — all three usually come from the same cause, and it is not a mystery.
The library is the licence
When you pick a track inside Instagram or TikTok, the platform has already licensed it for that use. When you drop a track into an editor and upload the finished file, nobody has licensed anything.
The part that surprises businesses
Business accounts see a smaller music library than personal ones, because commercial use is licensed separately. A track your friend used is not necessarily a track you may use.
What happens when it is wrong
- The audio is muted, and the video stays up looking broken
- The post is removed
- Repeat matches count against the account, and the account is the thing you cannot replace
The scheduling consequence
A video published through an API carries whatever audio is in the file. It cannot reach into the in-app library. So a scheduled video needs music that is licensed for you — your own, a library you pay for, or none.
Silence is not a failure. Most video is watched muted anyway, which is why captions matter more than a soundtrack.