Bug#931568:

2019-09-15 Thread Spielwarenkontor 
Ok, could temp solve it bydowngrade fetchmail to stretch version.

vi /etc/apt/sources.list
#add 
deb http://ftp.de.debian.org/debian/ stretch main non-free contrib
deb-src http://ftp.de.debian.org/debian/ stretch main non-free contrib

apt-get update
apt-get install fetchmail/stretch

Bug#931568:

2019-09-15 Thread Spielwarenkontor 

Same here in Debian stable - just upgraded from stable stretch to the
new stable buster and broke production fetchmail system.

client
Sep 15 18:14:01 boark fetchmail[4250]: OpenSSL berichtete:
error:141A318A:SSL routines:tls_process_ske_dhe:dh key too small

server
Sep 15 18:18:01 example.com dovecot: imap-login: Disconnected (no auth
attempts in 0 secs): user=<>, rip=10.0.0.1, lip=192.168.1.1., TLS
handshaking: SSL_accept() failed: error:14094410:SSL
routines:SSL3_READ_BYTES:sslv3 alert handshake failure: SSL alert
number 40

Please escalate this bug.