Primary site server cannot install new DPs

Question

I have a new Site server. The built-in dp on it works a treat. Anytime I try to add a new DP (multiple machines tried), I get the same error. "Distribution Manager failed to install distribution point on computer. Possible cause: Distribution Manager does not have sufficient rights to the computer. Solution: Verify that the site server computer account is an administrator on the distribution point computer.

I have put the group that I use for SCCM local admins in the local admin group on the new dp, same error. I removed that and put specifically the site server computer account in there, same error.

I have 2 drives on the DP: C (which has the NO_SMS_ON_DRIVE.SMS file) and E. When I setup the distribution point I have tried both automatic drive selection and specific to E. No change. Checked security on the E drive and the computer account of the site server is in there with full control.

When checking the distmgr.log file on the site server, the main standout errors are :

1. The distribution point is not installed or upgraded yet.
2. Failed to install file on REMOTEDP, failed to copy contentauthmodule.dll to NEWDP Win32 error =64

There is nothing in the PkgXferMgr.log as it never has a job created by Distribution Manager.

I can access the remote DP's $admin share from the site server with no problem.

I have seen this issue all over the internet and have tried various fixes, but none have worked. I've been banging my head against this wall for 2 weeks and would really appreciate some insight as to what is going on.

Thanks in advance