You can use any of the following ways to confirm domain ownership:
Make sure that the file:
Opens at an address like http://yourdomain.tld/secret_code.html, where “yourdomain.tld” is the name of your domain, and “secret_code.html” is the name of the uploaded file.
Contains nothing but the verification code.
If you can't open the file at the address above, this might mean that the file hasn't been updated on your web server yet, or it was created and added incorrectly. Check the settings again. If waiting and checking settings didn't help, contact your hosting provider's support service and ask them to help you create the correct file in the site root.
Make sure that the desired address points to "mail.yandex.ru". To do this, make a DNS request using a dig tool (for example, http://www.digwebinterface.com):
Enter a request in the format “yamail-secret_code.yourdomain.tld” as the site address.
Choose the CNAME type of record and send the request.
If the CNAME request has been added correctly and taken effect, the response should be something like this:
yamail-secret_code.yourdomain.tld. 21600 IN CNAME mail.yandex.ru.
If you don't receive a response, check the settings again. If waiting and checking settings didn't help, contact the support service at the company that hosts your domain. Ask them to help you create a CNAME record for a subdomain.
Make sure that the correct address is shown in the Whois information about the domain. To do this, use the http://www.whois.com/whois or http://www.whois-service.ru service. The contact address must be specified in the Admin e-mail: field.
If the address is missing, a different address is shown, or the contact information is hidden, either the changes haven't propagated yet, or the settings were not made correctly. Check the settings again. If waiting and checking settings didn't help, contact the domain registrar's support service. Ask them to help you change the email contact address.
Make sure that delegation was performed correctly and the changes have taken effect.
The current state of DNS, using a dig tool on the page http://www.ip-ping.ru/dig/?host=&rt=3&server= or http://www.digwebinterface.com/?hostnames=&type=NS&ns=resolver&useresolver=18.104.22.168&nameservers=.
If the list and names of NS servers don't match or the NS servers don't respond to the request at all, either the changes haven't propagated yet, or the settings weren't made correctly. Check the settings again. If waiting and checking settings didn't help, contact the domain registrar's support service. Ask them to help you delegate your domain to the servers “dns1.yandex.net.” and “dns2.yandex.net.”.
If the recommendations above didn't help, or you have another question related to confirming domain ownership, use the feedback form to send a message to the Yandex.Mail for Domain support service.