@Anonymous User
Welcome to the forum. You may well find you can add your pass no problems today, but if you are still having trouble and trying a different device/browser doesn't work (if you have a code to enter for a free offer you can try entering it on the My Account screen of the NOW TV app on a box or some other devices such as game consoles for example) then pop onto live chat and they can check what's stopping it working.
You can get to live chat from the Contact Us page
https://help.nowtv.com/get-in-touch
(expand the Anything Else section at the bottom for options)
