One of my colleagues borrowed my iPhone to check on its installed applications. He then touched on the finger scanner and eventually asked me if that's working. I nodded yes but when I tried it myself it just opened but it did not went through. That's when I realized that it again has a problem. I tried almost every applications but all were in the same condition.
When I get home from the office, it was my first assignment to fix this apps problem. I have tried various ways such as:
-deleting some of the apps as well as those mails downloaded as there could be a memory issue
-resetting the settings
-rebooting the phone
-removing and putting back the SIM card
but unfortunately these things did not work.
The next thing I did was having the iPhone plugged to my desktop to have it synchronized again to iTunes. After a few minutes,I clicked on the apps and glad to have seen them functioning again.Happy to have it resolved myself without the need for me to ask for a professional technician to do it with fees. ;)