CM MAC Not Identified

nhrox Hello and thank you for reaching out via our Xfinity Forum today. If you are trying to set up an internet connection for NOW Internet and you receive an error message stating that the CM MAC identifier is not valid, there are a few steps you can take. First, make sure you are eligible for NOW Internet service by checking your address. If your address is eligible, you can add NOW Internet to your cart and proceed to checkout and a modem will be sent to you. However, if you already have certain Xfinity services that are not eligible to mix and match with NOW products, you may not be able to add NOW Internet at this time.