Unfortunately you don't provide any information about the media detail

For example if the media are ancestry census medi items downloaded as part of a merge operation these will not be uploaded as they are already on Ancestry.com

FTM advises you about this as part of a sync operation involving media

Media that you have marked private in FTM also will not be transferred

Also some media file types are not supported and will not be uploaded

Perhaps you could be a bit more specific in your post?

John D