TLS handshaking: wrong version number

leifnel

I’m trying to connect to mailcow from the built-in mail client in windows 11.
I get this error message in the dovecot log:
TLS handshaking: SSL_accept() failed: error:0A00010B:SSL routines::wrong version number

The watchdog connects regularly:
user=<>, rip=172.22.1.13, lip=172.22.1.250, TLS: Connection closed, TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)

I have had it working some months ago….

esackbauer

Which port are you using for IMAP? And which kind of encryption?

leifnel

The microsoft mail client isn’t particularly helpful, but it’s using port 993

esackbauer

The MS Mail App is already quite dead:
https://techcommunity.microsoft.com/t5/outlook/mail-amp-calendar-apps-will-be-replaced-with-new-outlook-for/m-p/3850309
I would suggest you use Thunderbird, Mailspring, BlueMail or EM Client instead. With the new “Outlook” App replacing “Mail” Microsoft will store your password…

leifnel

esackbauer

The old client already stores the password. What is the difference?

esackbauer

leifnel
The old client stores the password locally. The new Outlook (the Windows store app) is storing it on Microsofts servers.
https://mailbox.org/en/post/warning-new-outlook-sends-passwords-mails-and-other-data-to-microsoft