Data cannot be shown in report and Gantt view

Dear all,

I am a user using this system to manage our projects and related manpower allocation. Recently we have came across some problems during planning. We entered the data in the planning section and conducted planning calculation. After that, the planned date did appear in activities >> progress >> dates and duration. However, the planning data cannot be shown in the reports and Gantt view. Such issues did happen several times while using.  

Did somebody also come across similar issues? How did you fix such issues and prevent it from happening again?

Thank you so much for your reply.