Hi again

IMAP Login thankfully works on imaps port 993 with plain SSL.

But now I get the same issue with SMTP.

Port 465 which traditionally is used for smtps via plain SSL is
closed.

Port 587 advertises STARTTLS:

Trying 2603:1026:c0b:16::2...
Connected to outlook.office365.com.
Escape character is '^]'.
220 ZR0P278CA0005.outlook.office365.com Microsoft ESMTP MAIL Service ready at 
Tue, 18 Jul 2023 14:43:40 +0000
ehlo example.com
250-ZR0P278CA0005.outlook.office365.com Hello 
[2001:4060:1:4133:9afa:9bff:fe4a:aa55]
250-SIZE 157286400
250-PIPELINING
250-DSN
250-ENHANCEDSTATUSCODES
250-STARTTLS
250-8BITMIME
250-BINARYMIME
250-CHUNKING
250 SMTPUTF

But same as on the IMAP port, after issuing STARTTLS no more
communication is possible.

Can be checked with openssl:

$ openssl s_client -starttls smtp -connect outlook.office365.com:587

Cert Validation works, but then the Server is silent and does not
accept any SMTP commands.

Same on port 25 btw, which is blocked by many ISP. But wait, hotmail
hopefully also uses TLS for emails from server to server. STARTTLS
should still be working there...

$ openssl s_client -starttls smtp -connect 
hotmail-com.olc.protection.outlook.com:25

Same issue, checking our mailserver logs if I see anything about
STARTLS failing towards Hotmail etc.

Mit freundlichen Grüssen

-Benoît Panizzon-
-- 
I m p r o W a r e   A G    -    Leiter Commerce Kunden
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