Sorry, we were unable to deliver your message to the following address. .... Message expired for domain arnold.co.nz. Remote host said: 452 Too many recipients received this hour [= RCPT_TO]
More recently just getting. Mail server for "arnold.co.nz" unreachable for too long.
arnold.co.nz resolves to a fixed TC IP address. Ironically my paradise.net email address (that presumably goes through a different TC mail server, but ends up in the same mailbox) gets through fine.
188.8.131.52 tm3.bullet.mail.sp2.yahoo.com is the last IP address in the mail header of the bounce back to my sister if I read it right.