Do you have another Studio Pro instance running? It seems port 8083 is in use, this is used by the native packager port. Newer Mendix releases will use a different port if it is occupied. This can happen when you have multiple instances open, even if the other one is not running. Also, Studio Pro sometimes leaves the packager running after a crash. Rebooting the machine will kill these leftover processes. You can also close all Studio Pro instances and kill leftover node processes, assuming you don't have any other node stuff running. If unsure, reboot to be on the safe side.