Your PR card application number is not the same as your PR application number. You probably won't know your PR card number unless you call IRCC.HI I am not able to link my GC key with PR CARD, Can someone advise. GC key says Application number is not valid for described category Which is "Permanent Resident Card"
Also, I have tried to link mine but it doesn't work, I called IRCC and they don't know why it doesn't work so I raised a webform for a technical issue, still waiting.