Why Yandex.Mail gives errors while delivering letters from the subdomain?

Good day

Added mailgun subdomain of the form the postman.domain-name.com. The domain is purely for email. Created 5 DNS records of which they asked for verification. Domain confirmed and connected to the service.

Now, send him letter to your e-mail in Yandex.Mail.
If the "From" field is the address noreply@domain-name.com - a letter appears in the mailbox Yandex.
If the 'From' filled as noreply@postman.domain-name.comthe letter is not delivered, and the mailgun interface it is marked with the error:

5.2.2 Mailbox size limit exceeded 1578276298-gyMZMkM6XP-4vS4AhHG

Search for this message gives the page of Yandex, where they write that it is necessary to log in to the web mail interface to this bug fix. Okay, open your web mail interface, send a mail noreply@doamin-name.com and I see it in the Inbox. Then, without closing the browser tab with the mail interface, change in your application to the address on noreply@postman.domain-name.com the letter comes in the mailgun log error quoted above.

Why is this happening? I have no ideas at all...

If you ignore and leave noreply@domain-name.com as the sender, then cidet MS Outlook emails to SPAM, because the main domain connected email from Google via G Suite

Update 1: Tried sending through HTTP API and via SMTP. The result in both cases is the same
Update 2: the Error POPs up only if the domain was created in the region U.S./North America. For domains from the region of Europe, this problem does not occur. That is, if not sanctions... haha ((
April 4th 20 at 00:54
1 answer
April 4th 20 at 00:56
The error message tells you about the exhaustion of the limit of the mailbox. Or place over or the mail size is exceeded.

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