2nd set of xFi Pods - Still not working!!

I have not been able to connect a set of xFi pods.  I've tried them in various outlets, tried to enable them manually, spent time on the phone w/support and had a tech come out.  He told me to go to the xfinity store to swap them out.  Just brought them back and have the same issue.  Getting an error "try again".  Is there something on the router/modem that needs to be enabled to use these?