Go to Your project location (Right Click on solution explorer and Open folder in file explorer). View Hidden Files. open .vs folder. Go to config folder and open applicationhost.config file with notepad and find your port which is in use and change with different port number it should be grater then older port and save file then close and run your project again and change your port to new port number.
Assuming you're in Visual Studio and using the built in web host rather than IIS, select the Web Application project within Solution Explorer (if you have more than one project), and either right-click on the project folder and select "Properties", or choose "Project | [ProjectName] Properties" from the menu.
Switch to the Web pane and check the following options in the Servers section:
Ensure the first drop down is set to "IIS Express" and then update the port number in the "Project Url" field:
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