Datatables invalid json that's actually valid?

My json is passing validation. But when data tables pulls it from ajax I get the invalid json error. What am I missing?

My json:

[{"category":"","user_display":"","appchk_txt":"Driver's License ","appchk_rid":"121","user_txt":"","appchk_cod":"DL"},{"category":"","user_display":"","appchk_txt":"Reference ","appchk_rid":"128","user_txt":"","appchk_cod":"RF"},{"category":"","user_display":"","appchk_txt":"Reference: School Counselor ","appchk_rid":"149","user_txt":"","appchk_cod":"11"}]