[Twisted-Python] SMTPClient disconnects following STARTTLS

[Burak Arslan]

Hello,

I'm trying to deliver mail using twisted.mail.sendmail (version 18.9.0)

Delivery attempts to some servers fail either with disconnections or
timeouts following the STARTTLS command. When I disable STARTTLS (by
patching tryTLS()) message delivery succeeds.

So is there a way to log the TLS handshake process to be able to
understand why the TLS connection cannot resume? Any suggestions for
troubleshooting this? A dry ConnectionDone doesn't tell much.

Is it possible to make t.m.sendmail() attempt another delivery without
STARTTLS?

Best regards,
Burak ARSLAN