iPhone and mail server with encryption?

Question

iPhone

I set up a mail server in the organization where I work now (with B&S, as it should be). The problem is that all adequate mail clients known to me (Thunderbird, Evolution, Roundcube) work fine with it, but the iPhone does not work.
The configuration is as follows:
SMTP - Postfix 2.7 with authorization and mandatory TLS encryption:
smtpd_use_tls = yes
smtpd_tls_auth_only = yes
Ok, when I tried to connect on port 25 with SSL enabled, the iPhone cheerfully informed me that my server does not support authorization (!). A brief google showed that checking the available ways to connect to the server on the iPhone is stupid, like a brick, so it will never connect to port 25. Okay, no problem - I reconfigured the server, activated port 587, and here it is a miracle: an iPhone with exactly the same parameters was able to connect to the server without any errors. How the port number affects authorization and encryption - I can’t imagine, the server works identically on both ports.
And the questions would not have arisen if it were not for IMAP. Here I have Dovecot, again, with TLS encryption enabled. As usual, the iPhone decided to be original and did not connect to port 143. Okay, no problem - I activated the outdated SSL (imaps) on the server and told the iPhone to use port 993. The iPhone connected to the server and even pulled in all the letters. Once. After that, it invariably reports that the server was not found and it is impossible to connect. Occasionally, it connects and pulls in at least the headers of new letters, but very rarely. Moreover, nothing depends on the connection to the Internet - both WiFi and 3G are one garbage. Logic suggests that the iPhone has some terribly low timeouts for some operations, so it reports an inaccessible server without waiting for a response. A brief googling again showed that the problem has been known for a long time and concerns not only my corp. servers, and even Google servers. The problem has already been solved at least two times, judging by Apple's reports, but as my dances with the mail server showed, things are still there. The solution I found is to use POP. For obvious reasons, this doesn't work for me.
Attention question: I have full access to the servers and the only task is to get the iPhone working with full authorization (both IMAP and SMTP) and full encryption. I cannot change the software on the servers (Postfix + Dovecot), but I can configure it as I please. What is it okay to do? Where to even dig? iPhone seems to be with fresh firmware (something like 4.3.2, exactly 4.x, I don’t remember further)

Answer 1

I also have a problem with iPhone & postfix, dovecot just can’t log into the server, I understand that it automatically adds a dog to the username, the log says that it doesn’t know such a user and that’s it, tell me who came across, stupidly add aliases Or is there some trick?