dovecot - Jul 2020 - problem with client using TLS

Hello!

On my testserver running CentOS8 I have installed dovecot v2.3.8.

I can connect to the server using claws-mail on my PC but can't
using K9-mail on android device.

Jul 18 12:24:57 imap-login: Debug: SSL: where=0x10, ret=1: before SSL
initialization
Jul 18 12:24:57 imap-login: Debug: SSL: where=0x2001, ret=1: before SSL
initialization
Jul 18 12:24:57 imap-login: Debug: SSL: where=0x2002, ret=-1: before SSL
initialization
Jul 18 12:24:57 imap-login: Debug: SSL: where=0x2002, ret=-1: before SSL
initialization
Jul 18 12:24:57 imap-login: Debug: SSL: where=0x2001, ret=1: before SSL
initialization
Jul 18 12:24:57 imap-login: Debug: SSL alert: where=0x4008, ret=582: fatal
protocol version
Jul 18 12:24:57 imap-login: Debug: SSL: where=0x2002, ret=-1: error
Jul 18 12:24:57 imap-login: Debug: SSL error: SSL_accept() failed:
error:14209102:SSL routines:tls_early_post_process_client_hello:unsupported
protocol
Jul 18 12:24:57 imap-login: Info: Disconnected (no auth attempts in 0 secs):
user=<>, rip=87.182.44.142, lip=185.84.81.115, TLS handshaking:
SSL_accept() failed: error:14209102:SSL
routines:tls_early_post_process_client_hello:unsupported protocol,
session=<uppwr7SqrrpXtiyO>
Jul 18 12:24:57 imap-login: Debug: SSL error: SSL_accept() syscall failed:
Invalid argument

Tried different settings without luck.

grep -v '^#' 10-ssl.conf
ssl = yes
ssl_cert = </etc/letsencrypt/live/smtp.dualbit.de/fullchain.pem
ssl_key = </etc/letsencrypt/live/smtp.dualbit.de/privkey.pem 
ssl_dh = </etc/dovecot/dh.pem
ssl_min_protocol = TLSv1.2
ssl_cipher_list = PROFILE=SYSTEM
ssl_prefer_server_ciphers = yes

Can somebody help solving this?

Kind regards

  Andreas

ratatouille skrev den 2020-07-18 12:33:
> ssl_min_protocol = TLSv1.2
> ssl_cipher_list = PROFILE=SYSTEM
> ssl_prefer_server_ciphers = yes
comment this lines, then i belive k9 works

if it still does not, then drop k9 mail

Hello!

Benny Pedersen <me at junc.eu> schrieb am 18.07.20 um 13:04:37 Uhr:
> ratatouille skrev den 2020-07-18 12:33:
> > ssl_min_protocol = TLSv1.2
> > ssl_cipher_list = PROFILE=SYSTEM
> > ssl_prefer_server_ciphers = yes  
> 
> comment this lines, then i belive k9 works
> 
> if it still does not, then drop k9 mail
Commenting just ssl_min_protocol = TLSv1.2 seems to solve the problem.
So I have the default ssl_min_protocol = TLSv1

Thank you!

  Andreas