new user question, all buddies not authorized

[Stephen Porter]

I've looked quite a bit for an answer, but have come up blank.

I installed Pidgin on a Windows PC, set it up with my mailbox.org account,
and Pidgin says the account is enabled. Yet when I try to add a buddy, I
get a "not authorized" error, "remote server not found."

I've tried inviting people on Gmail, Yahoo, and im at ddg.gg as a check, to
no avail. So what am I doing wrong?

Thanks,
Steve