Distribution fails for some DP's : Failed to make a network connection to ADMIN$ (0x4d8).

I am scratching my head to isolate the distribution fails for some of the DP, even tried to redistribute ends with same error.

If I verify the content status it show as below error.

Distribution Manager failed to connect to the distribution Point.

Possible Cause:Distribution manager cannot access the distribution point machine because of access permission issues.
Solution: Make sure that the site server machine account or site system installation account has administrative permission on the distribution point machine.

And I analyzed the "distmgr.log" file in Primary Server it shows below error in the logs, I was trying to find a solution but no luck.

Error occurred. Performing error cleanup prior to returning.
Failed to make a network connection to \\DP Server FQDN\ADMIN$ (0x4d8).
Cannot establish connection to ["Display=\\DP Server FQDN\"]MSWNET:["SMS_SITE=EM1"]\\DP Server FQDN\. Error = 1240

CAS, Primary server and account used are added as admins in DP servers Admin group. Admin share and C$ has already been enabled, manually verified to access it from both Primary as well CAS.

Even i tired to resolved the DP hostname and FQDN from Primary, CAS and vice versa. Kindly let me know, what causes this issue.

Thanks in advance.