My own header file is not recognized

I had my own header file cbuff.h with data structure, which I want to include in main.c but when I do it, the main function is not able to find this header file. May you help? Here are the screenshots.


Active project is selected correctly according the the project environment switcher?

A normal ‘build’ or Cmd+Shift+P → Rebuild IntelliSense does not resolve the issue?

Thank you, I switched the project enviroment as it listed under the link which you attached and it works. Thank you for your help.