Failed binding to authentication address * port 1812 as server freeradius: Address already in use

When I type the following command on my Ubuntu 16.04: **sudo freeradius -X** I've got the message: Failed binding to authentication address * port 1812 as server eduroam: Address already in use I've read previous topics related to that issue and their problem were that freeradius service had been running already. But in my case it's true. Here is output of the command: **sudo ps aux | grep freeradius**: tnur 1349 0.0 0.0 12948 932 pts/0 S+ 09:44 0:00 grep --color=auto freeradius There is no running freeradius service! What could be the problem in my case?