What is your travel history. this reason does not mean you have not traveled to Canada, it means you have not traveled to a country that requires a visa, like Europe, uk or Schengen.
Is the course you are applying for in line with your level of education? Does it provide a progression in your career or chosen career?
How much have you got financially and what was the proof you gave for it? You need the money for the course and 10k living expenses for the first year minimum.
Did you write an SOP?
Did you provide good to your home country?
What documents did you provide?