The following diagnostic is generating:

PDF attachment: A PDF file(s) of the Form NYC-222, Underpayment of Estimated Tax by Corporations, must be attached to the New York City return. Scan and attach a PDF copy of Form NYC-222 (Screen 3.2, Electronic Filing - PDF Attachments).

Solution:

1. Print NYC-222 to PDF
2. Go to Screen 3.2 Electronic Filing>PDF Attachment
3. Mark Send PDF attachment with federal return as No
4. In the New York City Information check Send PDF attachment with New York City return and choose Form NYC-222 from Form and line number on NYC return (Ctrl+T) dropdown box.