Hi Sanjib,
You haven't given us enough information about your setup to help. You also haven't shared any detailed error messages.
However, it's likely that you have not followed the "Production Installation" step of the installation guide. This step is REQUIRED in order to access the UI & REST API from a different PC. So, for example, you must be running HTTPS (on the backend at a minimum) to access the REST API from a different machine.