How to fix: 404 error in google apps?

Question

Domain Name System

Friends!
I have an old Google Apps. I have been using the free version for several years for one domain. Now there is a need to add another domain (NOT A alias). In the console, the domain with the status is active, users are being created, mail is running.
MX registered exactly as on the main domain.
@ A ip
www A ip
drive CNAME ghs.googlehosted.com.
mail CNAME ghs.google.com.
www CNAME my-domain.ru
@ TXT v=spf1 include:_spf.google.com ~all
@ NS dns1.yandex.net.
@NS dns2.yandex.net.
@MX alt1.aspmx.l.google.com. 5
@ MX alt2.aspmx.l.google.com. 5
@ MX aspmx.l.google.com. 1
@MX aspmx2.googlemail.com. ten
@mx aspmx3.googlemail.com. 10
Apparently there are some problems with CNAME.
When entering mail.my-domain.ru, a standard Google error 404 is displayed.
How to fix this?
PS: A parallel question, is it possible to change the main Google Apps domain?