It is taking Packages upwards to four hours of retrying to download Packages to Package Server before they are successful.
The following messages appear in the agent log file on the Package Server:
Begin download for package: Package Name and GUID
Beginning download for package id: {Package GUID}.
Download package sources from: HTTP://[server name]/Altiris/NS/Agent/GetPackageInfo.aspx?xml=<request resource="{GUID.EN_US}" version="1" type="packageServers" compress="1" totalTime="35" totalFailureTime="35">
<packages>
<package guid="{Package GUID}"/>
</packages>
<addresses>
<address ip="x.x.x.x"/>
<address ip="x.x.x.x"/>
</addresses>
</request>
Security key for package validation is missing from response. Previously stored key will be used (if exist).
Error while downloading package: No package sources returned by server (0x80070490)
Retry package: id={Package GUID} delay=720 secs at=1/7/2019 3:58:25 PM causedDelay=1 earliestRetryTime=
End download for package: Package Name and GUID Status: retrying
OnEndPackageDownload Package id = {Package GUID}. Status = RETRYING. No package sources returned by server.
ITMS 8.x
The Package Server was set to "Constrained."
By default, the Package Server will retry for four hours (240 minutes) before it attempts to connect to the Notification Server.
When a Site has only one Package Server, that Package Server cannot be "constrained". If it is constrained, it will prevent the Package Server from downloading the file from the Notification Server until the four hour mark is reached.
In the SMP Console, click on Settings > Notification Server > Site Server Settings > Site Management > Package Service > Package Service Settings and then look under the Constrained Package Server selection option and you'll see the following that shows your Package Servers and if they are set to Constrained or not:
Uncheck the "Constrained" box shown in yellow above.