Problem with Let's Encrypt Certificate

[@lbutlr]

On 2017-02-17 (09:58 MST), Bastian Sebode <b.sebode at linet-services.de> wrote:
> 
> Weirdly my friend uses the same Dovecot Version with Let's Encrypt on
> his Server and it works with Thunderbird without any flaws. Mine fails
> the same way in his Thunderbird and also in a fresh installation.

Well, at least you’ve narrowed the fault down to Thrunderbird.

Are you using TB through a proxy? Do you have a corporate LAN or an anti-virus that is behaving as a man-in-the-middle (Anything that claims to protect your web-browsing)?

Have you tried from a different connection? Maybe on a different machine with “identical” settings?

Usually errors like these indicate you are not getting the secured connection you think you are.

-- 
Apple broke AppleScripting signatures in Mail.app, so no random signatures.