To monetise a track on YouTube, you need to own the exclusive rights in a given territory. YouTube can only pay one rights holder for the master recording per territory.
Before setting a track to be monetised on YouTube, ensure you own the rights exclusively in the territories which you have set the release for distribution, where necessary, consider updating your artist contracts to include the exclusive YouTube rights.
if you need to adjust your territory rights for a release, you can do so on the "Release Details" page. This article will epxlain how: How do I specify territory restrictions on a release?
If you monetise a track that you do not own the exclusive rights to and a 3rd party also monetises the same track, the track will be in conflict and prevent it from being monetised.
The following examples are ineligible to set for monetisation:
- Content licensed non-exclusively from a third party
- Content released under Creative Commons or similar free/open licenses
- Public domain footage, recordings, or compositions
- Clips from other sources used under fair use principles