Were you able to fix this issue? The error message will usually indicate that either one of the information provided is incorrect. To check if your authentication information is valid, you can try to login our webmail service at: https://courrielweb.videotron.com/cw/displayLoginEnLegacyResidentiel.action
You could also update your password and review each email addresses in your online account. Under "Your Videotron services", select "Manage your Webmail account" in the Webmail category. If you do change it, please note the password requires 6 to 8 lowercase letters or numbers.
Some additionnal checks with your email accounts in our system may also be required. We sent you a private message to retrieve your contact information and call you back. Alternatively, our technical support is available 24/7:http://www.videotron.com/residential/contact-us