Good day.
We've checked your server. Seems like you've unpacked a distribution archive over the installation forlder, then tried to install it.
We recommend to uninstall WCS fully, then make a clean installation to the server:
1. Make a copy of 
flashphoner.properties file
	
	
	
		Code:
	
	
		cd ~
cp /usr/local/FlashphonerWebCallServer/conf/flashphoner.properties .
	 
 2. Stop WCS
	
	
	
		Code:
	
	
		sudo systemctl stop webcallserver
kill `pgrep java`
	 
 2. Uninstall WCS
	
	
	
		Code:
	
	
		sudo /usr/local/FlashphonerWebCallServer/bin/uninstall.sh
	 
 4. Remove all WCS traces from 
/usr/local
	
	
	
		Code:
	
	
		sudo rm -rf /usr/local/FlashphonerWebCallServer /usr/local/FlashphonerWebCallServer-*
	 
 5. Download and install WCS latest build
	
	
	
		Code:
	
	
		cd /tmp
wget https://flashphoner.com/downloads/builds/WCS/5.2/FlashphonerWebCallServer-5.2.1261.tar.gz
tar -xzf FlashphonerWebCallServer-5.2.1261.tar.gz
cd FlashphonerWebCallServer-5.2.1261
sudo ./install.sh
	 
 6. Restore 
flashphoner.properties file
	
	
	
		Code:
	
	
		cd ~
cp flashphoner.properties /usr/local/FlashphonerWebCallServer/conf/
	 
 7. Start WCS
	
	
	
		Code:
	
	
		sudo systemctl start webcallserver
	 
 Then, admin inteface should open