A required port is already being used by another process.
There are 2 possibilities to solve this problem:
1) Freeing up the port (recommended)
Please stop the application that uses the required port, or change its port.
To find out which process is using the required port, execute the following command in a PowerShell console:
Make sure that you replace <port> with the port that is used by the other application.
After the port is free, please restart the service of our software.
2) Changing the port (possible since version 6.4)
Navigate to the advanced setting and open the port options.
There, you can change the port. Please save the settings afterwards.
In case, the port is designated for communication between different hosts, please make sure to adjust the port configuration on both hosts and do necessary changes at the firewall when ports are changed.