> First, I tried mailbox.org, which I can generally recommend without reservation. Unfortunately, you can’t send emails from any address on your own domain without a workaround, so the search continued.

I had read about other problems about this mailbox.org service, but not this one. Anyone knows what's the catch when trying to send emails from your own domain?

I think he means that he can have a catch-all, but to reply from that address, there needs to be an alias created on the account