Hello Whusheerreaz58
I assume you are talking about the Swiss Half Fare Card for tourists, not the Half Fare Card for residents.
Make sure you have all names in capital and reselect the country of residence, change to another country and change it back. It may help.
If the issues persists, try to purchase the Swiss Half Fare Card from the Switzerland Travel Center. This is the travel agency jointky operated by SBB and Switzerland tourism, their webshop is less restrictive:
https://switzerlandtravelcentre.com/de/che/ticket/swiss-half-fare-card
Kind regards,
Roland