Well insufficient documents means your file is missing documents or proof.
i submitted a complete file supporting my business for 2 years (bank statements, insurance, proof of tax payments, auditing reports) i also submitted school and universities degrees for my spouse and i
you are also supposed to send proof of ownership of a house, shop or land
when they sent me the intent to reject letter it had my points result and it showed 0 for english and french that is why i took the exams and sent them the results.