In the IMAP Server in Dovecot 2.3.3 through 2.3.5.2, the submission-login component crashes if AUTH PLAIN is attempted over a TLS secured channel with an unacceptable authentication message. Upstream Bug: https://dovecot.org/list/dovecot-news/2019-April/000410.html
Created dovecot tracking bugs for this issue: Affects: fedora-all [bug 1709241]
No builds for F30 to fix this. I asked several times in bug #1672622, but no action has been taken there.