I think Proof of relationship is for someone who has direct relative(s) in Canada.
The reason I asked is because my application was cancelled due to the lack of my spouse's Police certificate.
When I logged into my account, I found the system structure is different from the time I submitted my application. Right now, the “Spouse's Marriage Certificate” section is disappeared and the uploaded “Notarized Marriage Certificate” document has been moved to the “Police Certificate” section. I am not sure what kind of system changes happened to MYCIC account but I am certain that I have prepared and submitted my spouse's notarized Police Certificate onto MYCIC account. I differentiate document name and there is no way that I would have submitted a wrong file.
I have submitted a CSE this morning, but I am also considering to resubmit the application...