It's saying something about compete authorship of work and having performed everything in the work. But of course we use some samples here and there. How does that work? The samples are cleared and come with a license to use commercially. Just used some drum samples and a vocal "hey" but I wrote and produced it.
Anyone know why I got this email? song is "Like a Boss": https://soundcloud.com/the-element-stud ... e-download
Thanks for any insight into this.

email from copyright office in Washington:
"We are contacting you to inquire about authorship. By checking “yes” to the three statements at the beginning of the application process, you were directed to the Single Application screens and charged a $35 filing fee.
The Single Application is limited to one work; created by a single individual author; where the author is the sole owner of all rights in the work; and all the authorship contained in the work and in the deposit is by the same author. For additional information about the Single Application, see http://www.copyright.gov/fls/sl04s.pdf .
In this case, it is not clear whether all of the authorship contained in the work and in the deposit is by the same author. Although you created the words and music to the song, it appears that there are additional performers on the CD or mp3 file that you submitted as a deposit.
If there are additional performers, please let us know and we will provide instructions for changing this to a Standard Application.
Or, if there are no additional performers, please confirm this."