elementdude92
I have a similar setup the an intermittent occurance of the "An error occurred while connecting to the AirPlay device “AirPort Express”. An unknown error occurred (-15000).". I have not yet determined the cause, but I do have a fix that has worked for me each time the error occures.
This solution is provided without warranty and you use it at your own risk! It does require some basic Unix/Linux commandline skills.
Do the following on the system hosting/running iTunes:
Open a terminal and at the prompt type: ifconfig (you may have to type sudo ifconfig)
You should see output similar to this:
system:~$ ifconfig
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
options=3<RXCSUM,TXCSUM>
inet6 [removed be me for security]lo0 prefixlen 64 scopeid 0x1
inet 127.0.0.1 netmask 0xff000000
inet6 ::1 prefixlen 128
gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280
stf0: flags=0<> mtu 1280
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
options=2b<RXCSUM,TXCSUM,VLAN_HWTAGGING,TSO4>
ether [removed be me for security]
inet6 [removed be me for security]en0 prefixlen 64 scopeid 0x4
inet [removed be me for security] netmask 0xffffff00 broadcast [removed be me for security]
media: autoselect (1000baseT <full-duplex,flow-control>)
status: active
en1: flags=8823<UP,BROADCAST,SMART,SIMPLEX,MULTICAST> mtu 1500
ether [removed be me for security]
media: autoselect (<unknown type>)
status: inactive
fw0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 4078
lladdr [removed be me for security]
media: autoselect <full-duplex>
status: inactive
p2p0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 2304
ether [removed be me for security]
media: autoselect
status: inactive
utun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1380
inet6 [removed be me for security]utun0 prefixlen 64 scopeid 0x8
inet6 [removed be me for security] prefixlen 64
Your first active network interface should be en0. If you have more than one network interface configured you might also have an en1, etc. Basically anything that has an IP address is an active interface.
In my case I have one active interface en0. I fixed the problem by running the following command "sudo ifconfig en0 down" - this will shut down the interface and effectively KILL ALL active and stale connection associated with it.
next I did a "sudo ifconfig en0 up" - turns the interface back on - if your using DHCP you will aquire an IP address or you pick up the a statis IP address if that is how you've configured your network preferences.
You can run the commands on each configured network interface to "reset" it; this procedure should work. I'd love to hear about your (or anybody elses) experience using this solution.
--Jonathan
PS: the links to Apple Support Articles, although still active, are no longer updated by Apple. I have found that these particular articles were not helpful.