Having this same problem. I just started my subscription tonight and when I open the program for the first time I see the message: syncing then the subscribe button pops up. I don’t know if this information will help, I do see a lot of TCP Dup Ack requests, TCP previous segment not captured, TCP retransmission, TCP fast Retransmissions, and even a few TCP Out-Of-Order messages. Hope that helps. I did check to see if those are a problem on my machine. Everything checks out on this end. Thanks for your time.
Launcher version 1.0.0-2039063+++Depot+UE4-LauncherReleases