am getting this error in windows
(Password propagation is not done. Either default encryption key is configured or no UNIX hosts configured to propagate password.)
then computer will join to windows AD but dns update fail.

Are you using DHCP for Linux server?
What kind of DHCP server are you using?
There are many cases when DNS server unable to use hostname of Linux machine that is using DHCP.
I recommend set manually IP address for Linux server and configure DNS server to use Linux server name for that IP address.
This should resolve your issues with DNS.

How are you adding Linux server to Windows domain? Is SAMBA configured properly on your server. I think you shall join your Linux server to Windows domain from SAMBA, it will add hostname to computer list in AD.

1- i have windows AD + Dhcp
2-do u mean that i have to reserve ip address from dhcp scop or what

not that i have already joined 4 redhat server to windows AD but after that am facing this issue
i can the redhat server in windows AD comuputer but it is not automatically registering the dns records.

Yes, And you should to add manually to DNS reserved IP addresses for your servers with their names and set static IP on servers.
Also, it is recommended to have static IP for servers rather than dynamic.

no i have static ip for the linux server when it regsiter to AD server it should add dns record automaticall as it before.

Add manually to DNS - it will solve your problem.
As far as I know, when adding computer to AD it does not add automatically to DNS.

but it should automatically added coz i have tried first time it was working succesfully