My corporate email is hosted by Office365. I think KMail is far more productive an email client than the Outlook Web Application (OWA), so I use IMAP to receive email and SMTP to send email.I can receive email fine, but on certain networks I cannot send mail. For example, GoGo Inflight Internet (gogoair) or some of the corporate networks of my clients. On these networks, I get the following error from KMail:Failed to transport message. smtp.office365.com: Socket operation timed outSending email to Gmail via SMTP through the same port (587) works fine.I have configured KMail to send email as follows:Outgoing mail server: smtp.office365.comPort: 587Encryption: TLSI have tried:Lengthening the socket timeoutDisabling IPV6Disabling TCP Timestampsbut I see no change in behavior.I don't see anything relevant in the journal, akonadi logs, or .xsession-errorsAnyone have a suggestion on what else I can try?
Kmail cannot send to smtp.office365.com
networking;email;kmail
You can verify connectivity to STARTTLS enabled services usingthe apps that ship with OpenSSL:$ openssl s_client -starttls smtp -connect smtp.office365.com:587If this succeeds, it will dump extensive information about theserverss SSL configuration and the handshake to the terminal.You should then be able to talk to the server using ordinary SMTP(send it an EHLO for example).Otherwise you get either a connection error or a timeout.In case of smtp.office365.com the handshake is successfulfrom here.For more protocols supported with the -starttls parameter seethe OpenSSL documentation:https://www.openssl.org/docs/man1.0.2/apps/s_client.html