I have no problems connecting to my wifi, however my sister is staying with me and lives in Ontario. Her provider is Rogers. Her i-phone was connecting at first but now is unable to. When she enters the password message comes back as incorrect password. She is getting rather desperate.
I would suggest "forgetting" the WiFi network on the iPhone, and reconnecting again. To do this, go to Settings -> WiFi -> Press the little "i" on the right of your WiFi network's name, then press on "Forget". Then simply connect again.
If the issue persists, I suggest rebooting the router (black device with the Videotron logo in front). Simply remove its power cable and connect it back in again.