Sending is not working, what's the problem?

Question

Bitrix24

Kind everyone, tell me in which direction to look, a rule is imposed on the mailbox, when a letter hits, a function is triggered that, based on the subject, searches for addressees in the created info block, then generates a letter and makes a mailing list. The problem does not always work mailing, maybe both on the first try and 3. At first I sinned on the function, after checking all the rules in it. Then I thought that the letter did not arrive at the mailbox, I climbed in, the letters all come. I caught a situation when you manually check the box, the rule works.
Disabled delete after reading in the mailbox settings.
There is a mechanism that deletes letters every 2 minutes, it would be clear why the mailing did not occur, because whenever the letter arrived, deletion occurred during this interval. But he created a situation when he sent a letter immediately after deletion and after a minute and a half, the letter was not sent, although the rule should be checked every minute. It turns out the main problem is that the rule does not start, but why?
Why does the rule work stably when checking mail manually .. As a temporary solution, maybe there is a method, something like check mailbox new messanges? But I can't find anything like it.

Answer 1

I found the code in the modules, now I understand how to programmatically launch a manual check. The following problem remains, all letters are deleted from the mailbox every 2 minutes, there is no agent, the admins say that they do not have a cleaning mechanism, there are no rules on the mailbox. How to understand who or what deletes letters, maybe there is some kind of deletion event log