a. ITMS 7.6.X;
b. ITMS 7.5.X.
Symantec Management Agent uses the Agent Connectivity Credential (ACC) to connect to site servers to download packages. In hierarchical environments the same credentials are used by "Child" Package Servers to download packages from "Parent" Package Servers. Currently, when there are different ACC configured Parent vs Child, Child Packages Servers will lose the ability to download package.
Configure the same ACC on Parent and Child (Children) server.