Usually users can post from any instance to any federated community on any server.

Unless the federation between lemmy.ca and Lemmy.ml is wonky/broken, one of the servers is overloaded, or they’ve explicitly forbidden it, you should be able to post there.

HR: last online 2023 years ago

I’m sorry, but management doesn’t approve any refactorings or rewrites, they only approve hotfixes and don’t budge, it’s been that way for millions of years.