I am self employed (freelancer and subcontractor) still triggers T2125. Industry code doesn't work, doesn't allow me to file!
Box 48 entries on a T4A are also self-employment/business income.
The industry code used to file your return via NETFILE is different than the codes found on the CRA site (CRA's list is for paper filers only). You can find the right industry code here: http://www23.statcan.gc.ca/imdb/p3VD.pl?Function=getVDPage1&db=imdb&dis=2&adm=8&TVD=118464 or post a description of your business here and we'll be happy to assist.
https://turbotax.community.intuit.ca/replies/2647998