I'm creating a time display when posting, can you guide me, or what should I study?

There's a secret error which you haven't told us about in your secret code which you haven't shown us. Nobody can help you fix that based on the complete lack of information provided.

Click the green "Improve question" link. Add a clear and complete description of what you are trying to do, what you have tried, and where you are stuck. Include the relevant parts of your code, and the full details of any errors.