Hi @David Jenkins ,
We could check if there is something wrong with the WAN optimizer, the issue could be resolved once we removed it.
If this way could not work, we could check them in following steps:
a. We could check if the SCCMADMIN account is used and it does have the access as a domain admin as well the local administrator group local DP
b. IIS installation has been checked during the DP configuration. Is it supposed to install and configure IIS?
c. Could antivirus and firewall be closed on the DP?
Here is the similar post we could refer to:
Distribution Point creation failed. possible cause : distribution manager does not have the sufficient access right to the computer
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