Microsoft Mail app and broken sending emails via smtp
The other day, my director asked me to find out why his brand new Microsoft Surface RT tablet does not want to send mail.
Googling only confirmed the fact that Mail App does not work with smtp both in "adult" Windows 8 and on tablets. No solution was found. Chatting with chat support with a Microsoft employee led me to get links to topics on Microsoft forums that I had previously found on Google.
The problem manifested itself as follows: when I tried to send a letter from the mail app, the message “user@mydomain.com is unavailable” appeared in the upper right corner of the screen.
In the Postfix mail server logs, I saw the following:
Nov 15 15:05:11 nanoweb postfix / smtpd [96503]: connect from user.host.ru [ip.ip.ip.ip]
Nov 15 15:05:11 nanoweb postfix / smtpd [96503]: Anonymous TLS connection established from user.host.ru [ip.ip.ip.ip]: TLSv1 with cipher AES128-SHA (128/128 bits)
Nov 15 15:05:11 nanoweb postfix / smtpd [96503]: disconnect from user.host.ru [ip.ip.ip.ip]
After rereading the MS forums, I found a message from a sapper who admitted that there was a problem with smtp and TLS, and all that was left was to wait for a software update. The fact is that if you uncheck “use TLS”, then the Mail app first tries to connect via TLS, because it sees the claimed TLS support in the server banner, but for some reason, cannot connect to the TLS server with a self-signed certificate. When working with SSL, it seems like the same thing happens.
And then I thought "what if Postfix has a separate port with TLS disabled?"
After digging in the manual, the following lines appeared in master.cf:
2567 inet n - n - - smtpd
-o smtpd_sasl_auth_enable = yes
-o smtp_use_tls = no
-o smtpd_use_tls = no
In the Mail app on the tablet I set port 2567 for sending, unchecked “use SSL” and it worked!
This solution is offered as temporary and intended for administrators of mail servers.
The problem exists for at least two weeks and is still not fixed.