Panel iframe from outside

Hello all, im tryng to make the panel iframe shortcuts to router webpage and nvr webpage
But it works only on local network, on outside it is blank page
Is there any way to make HA preload this page as an internal server
Well i can make port forwarding on router but that is not so secure

Are you using SSL to connect to Home Assistant from outside? If so, the warning in the docs you posted probably explains why it’s not working.