Same issue on my server.
2018/02/18 06:37 PM io.netty.util.internal.MacAddressUtil
WARNING: Failed to find a usable hardware address from the network interfaces; using random bytes: xx:xx:xx:xx:xx:xx:xx:xx
RISING WORLD SERVER STARTED
/home/rustserver/risingworld/scripts
STEAM BIND TO 0 (), PORT 4255, 4259
2018/02/18 06:37 PM server.Main
SEVERE: Rising World - 0.9.2.3 - Dedicated Server
Linux 3.16.0-042stab127.2 Java 1.8.0_161 (amd64) Memory: 2885 MB
____________________________________________________
RW SERVER: Fatal error occurred!
com.codedisaster.steamworks.SteamException: Error initializing Steam Server API
at server.i.a(SourceFile:75)
at server.Main.h(SourceFile:544)
at server.Main.initApplication(SourceFile:254)
at commons.JIWApplication.initialize(SourceFile:236)
at com.jme3.system.NullContext.initInThread(NullContext.java:87)
at com.jme3.system.NullContext.run(NullContext.java:130)
at java.lang.Thread.run(Thread.java:748)
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//START EDIT
I just did a full reinstall of the server, removed the whole dir ( Always keep a backup available. 
) and this didn't seem to fix the problem. A fresh install of SteamCMD didn't help either, nor did replacing both steamclient.so files with those shipped by steam do anything.
//END EDIT
//START EDIT2
Decided to enroll a new LXC container, rather then having it run under special user on a shared VPS.
Will let you know if I encounter any issues, still.
//END EDIT2
