In the process of creating and changing the dpi configuration (in the /etc/dpi/fastdpi.conf file) errors are possible, which can intercept with the start of DPI, it is recommended to make changes to a copy of the configuration file first, check it through the check command, and only then replace the original config and restart the DPI.

Example of recommended actions:

#create backup file
cp /etc/dpi/fastdpi.conf /etc/dpi/fastdpi.conf.new
#edit backup file
vi /etc/dpi/fastdpi.conf.new
#integrity test 
fastdpi -p -c /etc/dpi/fastdpi.conf.new
#Result check configuration : SUCCESS means that configuration is valid
#replase the original configuration file with a newly created one
cp /etc/dpi/fastdpi.conf.new /etc/dpi/fastdpi.conf
#restart dpi
service fastdpi restart