Login for router is invalid?

Try to contact the support for help

CHAT
Go to this page ,https://fizz.ca/en/contact-us, if you are not connect login
The business cours: every day from 8 a.m. to 9 p.m. (EST).
Wait 5 seconds for the bubble icon to appear at the bottom right of the browser and click on the icon to chat with support. Try a different browser if you have issues getting the bubble to appear.
If the chat bubble does not appear, this means that the number of sessions waiting for our answers surpasses our processing capacity. If that happens, send us a private message via Facebook Messenger or Twitter.
FACEBOOK
Your can also send a message via facebook messanger https://facebook.com/fizzca and click send a message (this is a bit slower)
CONTACT FORM
You can also fill a contact form from your account Once logged in, from the account panel go to My Profile → Contact Form (the subject are limited) and fill out the form and someone will email you back.

Do you have an antivirus in your device?

If not, you can try to reset to original settings by pressing and holding for 20 seconds the small button at the back of your modem, with a pen or a paperclip.

Make sure you are not mixing zeros and capital "o", or capital "i" and lowercase "L".

If nothing works, then you can try to factory reset the router. Press the small button behind the box with a paperclip or the likes for 10 seconds.

The new wifi password will be the one printed on the sticker on the box. You can change it back if you want.