I inherited admin of a DCS 400si. Have been tasked with setting barge-in on an extension. There are 2 COS setup, one with set secure on and the other with set secure off. I changed the extension to the appropriate COS (MMC: 301) and still get a "Barge-in Failed Security On" when I test barge-in on the extension.

Anyone have any ideas?

Have gone over related programming MMC:206 and 701

Yes - MMC: 206 is set to Barge-In without tone and MMC 701 is how I found out that the 2 COS have different secure settings.