After linking Yandex.Mail to my account, I keep receiving an error: “Yandex error 200 - occupied.” Why?

This error may occur if the domain name has been already taken by another user.

You have to confirm your domain as it is already used by someone else.

1. Go to https://connect.yandex.ru/portal/admin/domains
2. Select your domain.
3. Copy the meta tag code.
4. Paste it to Head. To add the code to Head on all the pages, go to Site settings → More → HTML code for Head-zone. Make sure that you have re-published all the pages after adding the code.
5. Confirm your domain ownership. Done.