https://services3.cic.gc.ca/ecas/changeaddress.doDid anyone have any problems accessing ECAS? I've never used it because I was checking GCKey. But IRCC asked to provide them with my permanent Canadian address through ecas on-line Address Notification service and it can't find my case.
"We were not able to identify you using the information you provided "
choose client ID and then fill in the fields,... should be pretty straight-forward. Alternatively you can also do it over the phone with an IRCC agent (if you're patient enough to reach one)