After installing SMP 7.5 SP1 package servers reporting to the several child servers were attempting to download packages but failing to do so.
The following error could be frequently seen in the agent logs.
Error while downloading package: Security key for package validation is required, but does not exist. Future package validation & processing is not possible. (0x80070057)
In order for a foreign package server to download packages from the parent sources, or to post to GetPackageinfo.aspx and get a response, the parent NS must trust the agent making the request. In order to trust it the server must have the public resource key of any computer attempting to communicate with it.
In this case the public key registration had not been forwarded to the parent NS by any of the child servers. As a result they could not be trusted.
Any package server that is trusted by the parent NS (or even the NS to which it reports) must be returned in the following query:
The root cause was that Replication had been turned back on for the parent, after the upgrade, but not the child servers. All child servers still had replication disabled.
In the NS console go to “Settings > Notification Server > Hierarchy” then right click on the parent NS (if being done from the child server’s console”.
If “Enable Replication” is an option then select it.
SMP 7.5 SP1