If you find the following in skedler log when you click preview ,
[xx:xx:xx] [INFO] [skedler log] - Creating Phantom instance...
[xx:xx:xx] [INFO] [skedler log] - Creating Phantom instance...
Or if skedler server crashes on preview
To resolve check for the following library. Skedler report engine requires the following library to generate report,
For Ubuntu/Debian
sudo apt-get install libfontconfig
For Centos/Redhat
sudo yum install fontconfig