Mail not coming to new mail server?

Question

Domain Name System

Good afternoon, tell me the solution to this problem:
Initially, mail was configured on Yandex, kerio connect was raised to transfer mail, the corresponding records were raised on DNS with priority on the internal mail server.
example.ru. 3599 MX 10 mx.yandex.ru 8.8.8.8 (85 msec)
example.ru. 3599 MX 5 mailsrv.example.ru 8.8.8.8 (85 msec)
example.ru. 3599 TXT "v=spf1 ip4:5.XXX.XXX.XXX/30 include:_spf.yandex.net ~all" 8.8.8.8 (85 msec)
A test address [email protected] has been created on the new mailer. Letters normally leave from it, when you send it back to [email protected], it gives an error:
[email protected]
SMTP error from remote mail server after RCPT TO::
host mx.yandex.ru [87.250.250.89]: 550 5.7. 1 No such user!
Tell me, is it better to wait up to 72 hours to update vsez DNS records, or is there a mistake?

Answer 1

Wait at least a day. When I transferred mail from Google to small soft ones, dns was updated for a day and a half.

Answer 2

What is the point of waiting if the sending mail server finds the Yandex server, and the error eloquently says that the user does not exist?
PS
UPD: I read it inattentively, I see that you are moving to Kerio. Then just wait.
Check here: https://www.whatsmydns.net/#MX/example.com

Answer 3

outgoing mail does not require opening ports
Does your daemon listen from outside at all?

Answer 4

How exactly a computer accesses the Internet depends solely on the routing settings on this computer.
And what VPNs you have up there, and with what they are made, is absolutely unimportant.
Specify the correct gateway.