I waited for over 1 day, while it's still saying "MX records for this domain have not been set up". Then I moved my domain from GoDaddy to Yandex, i.e. change the DNS server of my domain to dns1.yandex.net and dns2.yandex.net, and waited another 2 days, the message remains. But it doesn't block sending and receiving emails, I also added another emails accounts of my domain, it works perfectly ...