Hi pingfongcheung,
Could you show us a screenshot of the problem?
Could you tell us your firmware version: Settings > System > Advanced > About phone > Build number
Thanks for your help.
Hello! It would help me help you if you posted a screenshot of the problem as a reply to this comment. I like to think I am quite good at IT and could use resolving this problem to feed my ego. Let me take a blind guess while waiting for your reply. I'd like few details about your phone click here to see it's IP address iproyal.com. Perhaps the ethernet cable from your wi-fi router got disconnected. If the problem doesn't lie in mechanical issues just try visiting a gsm service.
