Citrix - Windows 7 Your account cannot be added using this server address....

This could be due to several things. Basically it means your client does not trust your server.

To fix a problem at the receiver end: Try adding your server's full https path to your IE internet settings -> security -> intranet sites or trusted sites as you see fit and see if that fixes your problem.

On the server end. Have you bound your default website to a certificate. If you have is it the right certificate for that server.

Another possibility is due to DNS not reading static IP addresses if DHCP is not enabled, see: CTX137003 Error: 'Cannot Add Account' on Windows RT Receiver

If you want to use this internally you can use self certifiaction by adding the Active Domain certificate services role to your Primary Domain Controller and then issue a Control authority for that PDC and then issue a Web Server certificate and apply it to the certificates on your StoreFront machine and bind to it in IIS default webs site bindings. See Microsoft's documentation as the exact mechanism changes depending on which server version you are using.