Hello Aditya,
Please check below.
1.Ensure the microflow is actually triggered by a button, on-change event, or page load.
2.Double-check that the microflow with the breakpoint is the one being executed.
3.Check if the breakpoint is having condition that is failing.
4.if you're using Mendix Studio Pro, make sure the debugger is connected to the correct running instance.
5.add few log message and check that is appearing to ensure that you are using the correct MF.