Cause
- A second instance of the program is running
- The given port is already in use;
- A firewall or antivirus is blocking the programm to open the port.
- The system is not correctly configured;
Solutions
- Check the details at the end of the error message;
- Verify that only one instance of the program is running;
- Change the used port in web server setting file;
- In the antivirus or firewall application allow the program to open the given port;
- Reinstall the programm.