[OSX] multicast socket issue spams log file

I'm using 1.5.2 on OS X 10.11.2. As soon as I start server, log file is always updating with message:

ERROR [DiscoverySSDPMessageListener] Cannot open multicast socket,will try again
java.net.BindException: Address already in use
at java.net.PlainDatagramSocketImpl.bind0(Native Method)
at java.net.AbstractPlainDatagramSocketImpl.bind(AbstractPlainDatagramSocketImpl.java:94)
at java.net.DatagramSocket.bind(DatagramSocket.java:392)
at java.net.MulticastSocket.<init>(MulticastSocket.java:172)
at java.net.MulticastSocket.<init>(MulticastSocket.java:136)
at org.serviio.util.MultiCastUtils.startMultiCastSocketForListening(MultiCastUtils.java:45)
at org.serviio.upnp.discovery.DiscoverySSDPMessageListener.run(DiscoverySSDPMessageListener.java:89)
at java.lang.Thread.run(Thread.java:745)

but it I'm not sure if it actually affects the server.

P.S. On a side note, I had issues with stopping/restarting server since 10.11: pressing Stop Server in the console app just freezes the app (after restarting console server is still running), and stopping server via launchctl doesn't actually stop it. Also, after some time server just stops appearing in DLNA server list (DLNA client is Samsung UE55JU7580) and only mac reboot helped fixing this. So I removed serviio's plist from LaunchDaemons and wrote simple scripts to start/stop the server manually which now works perfectly.

P.P.S. Not sure why, but recently my 4k videos started playing via serviio (before TV was able to play them only via USB HDD and TVMOBiLi server, and PLEX server transcoded them to 1080p ).

FYI: doesn't happen any more in 1.6 (as well as the point mentioned in P.S.)

[zip]

I remember there is some software on the Mac which binds to the Upnp port (1900 UDP), but takes it exclusively, thus any other UPnp software cannot get to it. You might have a look at it (ps it wasn't any known media server, I think it was something from Apple themselves)

you're right, SSDP uses that port: https://support.apple.com/en-us/HT202944

[zip]

SSDP is a protocol used by UPnP, but there was a particular app that didn't implement UPnp correctly