I have changed my DNS and the MX record has changed to domain.com mail exchanger = 10 hostedsecurity.biz.domain.com. Why? What happens to my mail in this case?
Usually such records appear if there is no point after the domain name in the settings of your DNS server (hostedsecurity.biz instead of hostedsecurity.biz.). To rectify the problem, correct DNS settings and the system will start functioning correctly. No mail messages will be accepted till the record is corrected.