Email certificate issue (dovecot)

Hi, I'm using my own IMAP server (dovecot). It is running fine on all devices (Meego N9, Maemo N900, Mozilla Thunderbird...) but my securely signed certificate seems to be wrong for the Jolla. My conf : server : mail.makelofine.org Encryption : STARTTLS (SSL tested too) Port : 143 (STARTTLS) / 993 (SSL) openssl confirms my certificate is OK : echo '' | openssl s_client -connect mail.makelofine.org:993 | openssl x509 -fingerprint -text So, what is wrong ?! PS : When i check the box to allow unsecure certificate, it is working. Of course I don't want to enable it as I have a offially signed certificate