There are several problem with this including total lack of SSL without the proper cert for that other domain, also Lemmy.ml’s IP seems to be running a reverse proxy so the internal IP that we would want to connect to is not visible to the world this is common for web security, the owners must set allowed domains and ports in their config file.

If none of that was a problem Lemmy itself does not do well with changing domains, as highlighted here: lemmy.nrd.li/comment/190200