I have an error with WCS3 activation

“Caused by: java.io.FileNotFoundException: /usr/local/FlashphonerWebCallServer/conf/flashphoner.license (Permission denied)”

The activation process is trying to write /usr/local/FlashphonerWebCallServer/conf/flashphoner.license file.
The process has not permissions to write this file. It is error cause.
Check permissions or start activation.sh script as root user.