If you see in the logs a request to get NWCredentials, this is, literally, what it looks like - a request to connect to a server using stored network (NW) credentials.
Very simply, the credentials indicated on the "Symantec Management Agent Settings - Global" policy page under Authentication.
On this page, you can either specify specific credentials, or you can use the Application Credentials, otherwise known as the AppID. The App ID is stored on the main page of the Notification Server Settings policy page.
The most important things related to this we should remember are: 1) With DS jobs, there is at this time no way to over-ride these credentials. A request has been made to modify things, but in DS 7.0, 7.1, and 7.2, there is no way around this, other than custom scripted jobs (more on this later). 2) Remember that we connect to the task server to which the client is assigned in DS 7.0 and 7.1. In DS 7.2 we modify things a bit to look for the closest package server (more research is needed to know if the NWCredentials issue changes in 7.2). That means that the Deployment share on the Task Server must be accessible using these credentials.
Scenarios to be aware of:
In Figure 1 below, we've built an environment with possible scenarios where problems may occur with this issue.