updated my old box to 20.04 focal fossa beta and dovecot stopped working on it

[Francis Grizzly Smit]

yeah the config matches that on my good working box dovecot config identical

postfix config differs only in the line where the server name goes both 
servers start

but 20.04's does serve the emails the log has the following in it
tail -F /var/log/mail.log

Apr  4 21:12:11 killashandra dovecot: imap-login: Disconnected: TLS 
initialization failed. (no auth attempts in 0 secs): user=<>, 
rip=192.168.1.11, lip=192.168.1.11, secured, session=<popvRHSilL/AqAEL>
Apr  4 21:12:30 killashandra dovecot: imap-login: Error: Failed to 
initialize SSL server context: Can't load DH parameters: 
error:1408518A:SSL routines:ssl3_ctx_ctrl:dh key too small: user=<>, 
rip=192.168.1.11, lip=192.168.1.11, secured, session=<GAGKRXSimL/AqAEL>
Apr  4 21:12:30 killashandra dovecot: imap-login: Disconnected: TLS 
initialization failed. (no auth attempts in 0 secs): user=<>, 
rip=192.168.1.11, lip=192.168.1.11, secured, session=<GAGKRXSimL/AqAEL>


wish I understood that telnet can connect so it's listening (or 
something is)

telnet killashandra.local 143
Trying 192.168.1.11...
Connected to killashandra.local.
Escape character is '^]'.
* OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE 
LITERAL+ STARTTLS LOGINDISABLED] Dovecot (Ubuntu) ready.
^]
telnet> quit
Connection closed.

an identical thunderbird set up works on localhost I use 192.168.1.11 as 
the server name on this entry so it resolves


help would be good

--

Francis Grizzly Smit