OK, maybe its just me, but here is another trick for anyone else who has this problem. OK, you added another machine. The tray icon turns red because you have not configure Backup for this. You open the Home Connector software and under Computer and Backup, you see your server. Right Click to configure it and WTF, the options are all greyed out!
Why? I did not waste time to figure it out. I just tried to solve it. With many way from the client side: restarting the Home Connector Software, restarting the client OS, disconnect and reconnect it from the Network etc. I almost wanted to reset my months running router. Then I found the solution. Here is what you do.
Use Remote Desktop into your SERVER. Launch the Home Connector Software on the Server. And yes, yes! The options are not greyed out. Its enabled. Just do it!
Thats solve this issue. There is also a similar issue when I experience the backup was skipped and I did a manual backup. However, the status still says it hasn't been backup in the last 6 days. I did the same thing on the server and instantly it was updated with the status that all backup was done.
What happened? Maybe Microsoft will have an answer, but I do not think many people has this same problem here. Maybe its just me, or just Microsoft OneCare... :)