From the image alone it looks like you may be having a network connection issue. Does the Command Center app give you errors anywhere else or just the rewards page? Troubleshooting 101 says you would want to make sure your internet is connected and your firewall is allowing the command center app to go through it, if all of that checks out, try reinstalling the command center application.
Its possibly also and issue with the way your trying to setup your rewards account(password doesn't match requirements kind of thing), though those issues usually spell that out for you. Possibly also a temporary issue with some HP server that the rewards program uses.