MyDNS problem - Can not config with Google App

[quannv]

@       IN SOA  ns1.mirex.vn.   quannv.vietinfotech.net. (
        2009051105        ; Serial
        28800             ; Refresh
        7200              ; Retry
        604800            ; Expire
        86400           ) ; Minimum

mail            86400   IN CNAME        ghs.google.com.
mirex.vn.       86400   IN A            210.245.85.211
mirex.vn.       86400   IN MX           10 ASPMX.L.GOOGLE.COM.
mirex.vn.       86400   IN NS           ns1.mirex.vn.
mirex.vn.       86400   IN NS           ns2.mirex.vn.
www             86400   IN A            210.245.85.211

But I can not ping mail.mirex.vn.
I don't know why

[till]

Most likely the google server does not answer on pings. This does not mean that anything is wrong with mydns.

[quannv]

Till, Can you help me to resolve this problem? I will provide more information if you want

[till]

But what is your problem? Pinging a mailserver is not a test for a correct mailserver setup, so if ping does not work it does not mean that there is a problem at all.