Agreed, so you cannot just say that there is an issue from my side, no matter that it is on my networking router, my computer, or my misconfiguration.
The truth is that after 3 hours later, the connection is stable now. Of course, I didn’t change anything or modify the configuration, but it is normal, anyway.
It might be an issue from the ISP provider, or something between Blizzard and me. I just wanted to share my experience and how the rule to impact a player of Blizzard. It can be identified a single event, even an abnormal incident. But, I believed there were more than me has the same experience this afternoon since there are fewer players will open a discussion here, and share the experience.