sendmail with DDNS hp-ux11.22

[Hiroyuki_1]

Hello . Please forgive my poor English . I'm new to sendmail and a home user . My workstation is behind the NAT router and has private class C adress . Currently I'm using DDNS (ZONEEDIT) for my personal domain . Almost all look fine but sending a mail to the other mail adress causes 20-30 min. delay and "Host name lookup failure" error in mail.log . Less people still uses DDNS in JPN and RC could't solve it yet .
Anyone has good suggestion ?
HP-UX 11.22 sendmail 8.11.1
Thank you .

[Hiroyuki_1]

Hello . This is self reply . Problem was so simple . I was thinking that any live nameserver IP addresses were OK in the /etc/resolv.conf entry . I just moved from another provider and I left previous nameserver entry of resolv.conf . But after I changed the nameserver to current one which were provided by current ISP , problems of sendmail has disappeared . Everything is fine . Thank you very much and I'm sorry for all .
regards,