Hi. You need to enter the same information that you entered in your PR application. For me, because I moved from one city to another in ON, I forgot which city that I put in the PR application. This caused several failed attempts. Then, I tried to put the actual family members (including myself) in the PR application. This, too, returned several failed attempts (adding to the confusion about the city). Finally, I entered the application number (starting with G without X at the beginning), I entered the correct city and I entered 1 in the field of the number of family members, and it worked!
So, I think that you need to make sure of the information you enter (the combination of application number (without X) + UCI, or family name and date of birth etc.. then the correct answer as for where do you intend to live (province and city) and finally for the number of family members, you need to enter (1) only regardless the actual number of family members (including yourself)..
If this all does not work, it is better to call IRCC and they will walk you through to make sure that you are entering the same information matching that in your PR application.
Good luck!