dcpromo fails adding 2nd DC

I’m trying to add a second domain controller to an existing domain in an existing forrest. At end of the dcpromo wizard after clicking Finish I receive the following error message:

The operation failded because: Failed to modify the necessary properties for the machine account SRVR2$.
Access Denied

I have applied GPO to Domain Contollers OU, Local GPO on member server and Administrators OU to Endable computer and users accounts to be trusted for delegation.

I have verified that both user accounts I’ve tried are members of the Administrators, Domain Administrators and Entriprise Administrators groups.

Any ideas on what could be the problem and how to fix it?

Thanks.