cannot receive emails after dns provider change

Hi, I have exchange 2003 server, worked fine until I changed my dns provider from dyndns to netnames. webmail is accesible, but receiving email and openvpn doesnt work. i have waited 3 days, no luck.
ip address static, all records from dyndns were recreated on netnames?
do i have to configure something on echange? but then why openvpn doesnt work?