Soooo… I’ve done deactivate Jetpack modules, one at a time, per your suggestion; and I guess I’ve found the culprit.
The allegedly troubled module is Photon.
Maybe it’s because the content is stored in WordPress’ place so when the connection is disturbed then the content couldn’t show up 😐
Anyhoo, thanks for the reply and assistance though 😀 Hope you guys can work this out and fix this plugin. Jetpack is one awesome plugin, and I hope it can be better in the future with the help from you guys 🙂 Thank you very much for your kind attention.