I was having the same problem and found a solution.
Once you click "Grab your offer now!" it opens the web page. In the web address box the NOW TV pass code is at the end of the address, copy it and go back to manage your passes and paste it there. It worked for me.
Live chat works for me using MS Edge or Fire Fox.
Should you need to contact live chat, open the link page below, select the most appropriate category, then select the nearest help topic, then move half way down the screen page and click the green drop down arrow underneath How to Get in Touch to reveal the live chat button.