Can Soundtrack music be used on YouTube?

Hi everybody,

few days ago I have uploaded on Youtube a video containing a music taken from Soundtrack Pro (fc studio2).

I have received an email from YouTube stating that

"your video may include contents that are property of IDOL, but it is still available on YouTube. Sometimes there may be some advertising besides your video".

What should I do?

Is Soundtrack music free from royalties?

Why YouTube sends me such an email?

Thanks a lot for you help.

😕