Letters to Yandex mail do not reach, what could be the problem?

Question

Yandex

We registered a domain, delegated it to Yandex, everything is ok.
Created mailboxes on the domain in pdd.yandex.ru
The mailbox account is activated, the passport is full
When sending a letter to the created corporate mailbox, a non-delivery report is received:
Unfortunately, your letter cannot be delivered to one or more recipients:
[email protected] mails.ru
SMTP error from remote mail server after RCPT TO::
host mx.yandex.net [87.250.250.89]: 550 5.7.1 Policy rejection on the target address
We recommend that you check that the recipient addresses are correct.
Moreover, if we try to send a letter ourselves, we indicate the correct recipient's mailbox
We see:
An error occurred
Incorrect recipient's address
We do not see any restrictions in the account. We go in norms, no squeaks, no screams.
Support is sooooo slow responding with templates - it's useless to communicate with them

Answer 1

and here is the answer
This problem is caused by the fact that the registration of your login [email protected] seemed suspicious to our security system.
In order to fix the problem with sending and receiving emails, you must provide valid personal data on the https://passport.yandex.ru/passport?mode=passport page. In the same place, you will need to bind a mobile phone (link "phone numbers"), if you have not already done so, and, if a captcha (control characters) request appears, enter it. After that, the blocking will be removed automatically.
Please note that it will take several hours to remove the lock - during this time the system should receive and remember the changes you made.