Is the portal you need reachable right now? We check the public sign-in pages of Canada's immigration portals from our own server and show what we see, with 30 days of history and any downtime patterns we've noticed. This is reachability from our vantage, not official uptime, and never your own session.
“Best time to try” and downtime patterns are observed from our own checks; they are not an official maintenance schedule. When a portal is unreachable for us it may still work for you, and vice versa. Always confirm on the official page before you rely on it.