though I have completed all courses and Quiz, My examination page seemed as grade out. why is this?
You mean greyed out?(disabled)
When was the deadline?
Please check overview page
It will show details/status
As I can see, you had opted for M001-2019 January offering which ended on 29 January. If thats not the case, check the Overview page and send a screenshot.
If yes, please register for the current one.