How to connect mail to Bitrix24 using a sapo-signed certificate?

Question

IMAP

Actually a question.
Support asked a question, but they have answers only after 32 hours.
When I try to connect, I get an error: "Error connecting to the server."
The server has a self-signed certificate installed.
Bitrix has an option in the connection settings of the same name (self-signed certificate), but even using it nothing comes of it.
Where to dig?
PS
Clients work with mail via IMAP without problems through mail programs.