Alright,That might be part of the problem. To approve a study permit for a Master's, IRCC generally wants to see no individual scores below 6.5. If you can, I would strongly recommend re-taking IELTS and achieving a higher writing score.
But the prospective University need a overall score of 6.5 with individual 6 on each section.
It would be bit difficult to reapply for ielts again as my joining is jan 1