Please see this link
https://www.canada.ca/en/immigration-refugees-citizenship/services/application/application-forms-guides/complete-0008-5669.html
Question 3
Enter the total number of family members included in your application. This includes yourself and any
family members, regardless of whether they intend to accompany you to Canada or not.
For refugee claimants in Canada only: Enter the total number of family members included in your application for refugee protection who are with you in Canada.
I have only me in Canada but I have 4others back home. I put 4 as the answer to Q3
that was my mistake, When I put 1 I was able to link the paper application to the online account
Try accordingly if you had done the same mistake