Can't sign up for a zoho mail account

Can't sign up for a zoho mail account

please i want to sign up for free personalize i have change the mx record at my domain manager but i keep receiving this error message "We are unable to process your request now. Please try again after sometime or contact support@zohoaccounts.com"
The domain name is - nilessng.com, kindly help enable me on Zoho Mail. Thanks