Updated 16 july 2018.
I am being hit by spam in Chinese, which often disables my firstname.lastname@example.org 33mail account. This may give a 422 SMTP error to the sender.
email@example.com is becoming increasingly intermittent, it has been down a week at least.
Twitter is @CathyCathyFox and working though I could not get in for a few days.
I will try and get another email address soon due to the above problems.