I have several reports that the setup using a support email address going to a private category stopped working even when “Allow email from unknown addresses” is checked. Apparently there is a contradiction between: an existing user sending an email to that address, when they do not have access to the destination category an unknown address sending an email to the destination category Both should be working, but in one case, the email is rejected with: Email::Receiver::InsufficientTrustLevelError This is quite annoying since it used to work!