I had a problem where I would distribute packages to DPs, but not all DPs would receive the content.
The problem was because the Remote Differential Compression feature in Windows Server was not enabled (could be BITS for you). Add the feature from the Server Manager console and then wait. Review the distmgr.log and it should show that the content has been distributed.
Another issue that you may have if there are missing ‘required’ services:
distmgr.log: Package #AXC00001 does not have a preferred sender.
The moral of the story? Make sure all the required services are installed and running.