Site not displaying correctly

I've just configured a new Plone v6 installation and can acces http:// localhost:3000 ok on the server. When I access it on a PC on my network through 10.x.x.x:3000 the page does not display correctly. I'm unable to attach/imbed a screen grab for some reason, but the page displays in a very basic format with no logos or anything. Firewall is off

Also when I try to log in as admin I get 'Cannot POST /login' and the URL shows as 10.x.x.x:3000/login?return_url=http ://localhost:3000

Clearly I'm missing something here but I can't see what. Can anyone help please?