Why mail programs do not login account?

Question

Yandex

When creating corporate mail on Yandex, I cannot access it using mail programs such as outlook and thunderbird. You can go to the web face, there is permission to access the mailbox using mail clients, both via imap and pop3.
Outlook asks endlessly for a password upon completion of the login, and thunderbird "I can't log into the server ...".
This problem is only with newly created accounts, what could be the problem?

Answer 1

Recently, accessing corporate mails on Yandex through third-party applications, specifically for new mails, is obtained only through application passwords.
Yandex support does not openly say that it is impossible to enter third-party applications through ordinary passwords, but strongly advises using application
passwords then for new ones it is disabled by default, plus if you put it, a warning pops up.

Answer 2