Ssl error with offlineimap version 6.6.1 (debian package)

[Nicolas Sebrecht]

On Sat, Feb 06, 2016 at 05:40:42PM +0100, Leandro Noferini wrote:

> My imap server is courier with an selfsigned certificate and it worked
> fine for many years but some days ago it began to give me this error:
> 
> leandro at tricheco:~$ offlineimap -a BBs

<...>

> ERROR: Unknown SSL protocol connecting to host 'bbs.cybervalley.org' for repository 'RemotoBBs'. OpenSSL responded:
> [SSL: SSL_NEGATIVE_LENGTH] dh key too small (_ssl.c:590)

<...>

> What could be the error?

SSL defaults have change. Check your configuration, especialy
ssl_version and tls_level:

  https://github.com/OfflineIMAP/offlineimap/blob/master/offlineimap.conf#L681

OfflineIMAP must be configured to enable a protocol that the server
provides.

Also, you might like to check the output of --info.

-- 
Nicolas Sebrecht