Unable to log on to customer portal because "unknown email"

I am unable to access the Avast Customer Portal because the e-mail I entered is “unknown”, apparently. It is the same e-mail listed in my order confirmation and the e-mail to which I receive notifications from Avast. It cannot be unknown. The e-mail is lilly.laanepere@gmail.com
After having trouble with Avast Premium cleanup auto-renewal (still unresolved), I wanted to log on to make sure the VPN SecureLine auto-renewal is off and I won’t be charged for something I do not want. Any suggestions as to how I should proceed?