1. Tried to reboot ROC 23. Found that both TS1 and ROC23 (in the counting house) hung up. Couldn't telnet.
2. Powercycled the router in the counting house. Got TS1 and ROC23 back.
3. Rebooted ROC 23. But dithering still didn't work.
4. Checked with MCC a couple of times to make sure everything on their side is fine.
5. Did epics reboot again.
6. Rebooted ROC 23 again.
Dithering started to work.
I guess the problem was that ROC23 happened to hung up while I was doing epics reboot the first time, and the solution is to do epics reboot again and reboot ROC23 also. However, such a coincidence rarely happens.
Figure 1