Warning [Main]: mixxx: cannot connect to X server

Mixxx DJ Software v2.0.0 - Command line options (These are case-sensitive.) [FILE] Load the specified music file(s) at start-up. Each must be one of the following file types: *.mp3 *.ogg *.opus *.aiff *.aif *.wav *.flac Each file you specify will be loaded into the next virtual deck. --resourcePath PATH Top-level directory where Mixxx should look for its resource files such as MIDI mappings, overriding the default installation location. --pluginPath PATH Top-level directory where Mixxx should look for sound source plugins in addition to default locations. --settingsPath PATH Top-level directory where Mixxx should look for settings. Default is: /root/.mixxx/ --controllerDebug Causes Mixxx to display/log all of the controller data it receives and script functions it loads --developer Enables developer-mode. Includes extra log info, stats on performance, and a Developer tools menu. --safeMode Enables safe-mode. Disables OpenGL waveforms, and spinning vinyl widgets. Try this option if Mixxx is crashing on startup. --locale LOCALE Use a custom locale for loading translations (e.g 'fr') -f, --fullScreen Starts Mixxx in full-screen mode -h, --help Display this help message and exit (For more information, see http://mixxx.org/wiki/doku.php/command_line_options)