Cannot execute Find! on my wife's iPhone & iPad

I have the iCloud binding up and running. I can display the battery level and the location on all my devices and on all my wife’s device. However, the “find my phone” functionality apparently only works on my own device. When I try to execute it on one of my wife’s device (which bind against a different iCloud account), the log shows:

2018-05-30 13:35:22.237 [WARN ] [g.icloud.handler.ICloudDeviceHandler] - Unable to execute find my device request
java.io.IOException: Server returned HTTP response code: 500 for URL: https://fmipmobile.icloud.com/fmipservice/device/f
lorian.m.graetz@icloud.com/playSound
at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1894) [?:?]
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1492) [?:?]
at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:263) [?:?]
at org.openhab.binding.icloud.internal.Connection.getResponse(Connection.java:107) [228:org.openhab.binding.iclo
ud:2.3.0]
at org.openhab.binding.icloud.internal.Connection.postRequest(Connection.java:97) [228:org.openhab.binding.iclou
d:2.3.0]
at org.openhab.binding.icloud.internal.Connection.findMyDevice(Connection.java:69) [228:org.openhab.binding.iclo
ud:2.3.0]
at org.openhab.binding.icloud.handler.ICloudAccountBridgeHandler.findMyDevice(ICloudAccountBridgeHandler.java:10
7) [228:org.openhab.binding.icloud:2.3.0]
at org.openhab.binding.icloud.handler.ICloudDeviceHandler.handleCommand(ICloudDeviceHandler.java:95) [228:org.op
enhab.binding.icloud:2.3.0]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:?]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?]
at java.lang.reflect.Method.invoke(Method.java:498) ~[?:?]
at org.eclipse.smarthome.core.internal.common.AbstractInvocationHandler.invokeDirect(AbstractInvocationHandler.j
ava:153) [101:org.eclipse.smarthome.core:0.10.0.oh230]
at org.eclipse.smarthome.core.internal.common.InvocationHandlerSync.invoke(InvocationHandlerSync.java:59) [101:o
rg.eclipse.smarthome.core:0.10.0.oh230]
at com.sun.proxy.$Proxy164.handleCommand(Unknown Source) [228:org.openhab.binding.icloud:2.3.0]
at org.eclipse.smarthome.core.thing.internal.profiles.ProfileCallbackImpl.handleCommand(ProfileCallbackImpl.java
:75) [108:org.eclipse.smarthome.core.thing:0.10.0.oh230]
at org.eclipse.smarthome.core.thing.internal.profiles.SystemDefaultProfile.onCommandFromItem(SystemDefaultProfil
e.java:49) [108:org.eclipse.smarthome.core.thing:0.10.0.oh230]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:?]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?]
at java.lang.reflect.Method.invoke(Method.java:498) ~[?:?]
at org.eclipse.smarthome.core.internal.common.AbstractInvocationHandler.invokeDirect(AbstractInvocationHandler.j
ava:153) [101:org.eclipse.smarthome.core:0.10.0.oh230]
at org.eclipse.smarthome.core.internal.common.Invocation.call(Invocation.java:53) [101:org.eclipse.smarthome.cor
e:0.10.0.oh230]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:?]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:?]
at java.lang.Thread.run(Thread.java:748) [?:?]

Is this related to the fact, that her devices bind against a different iCloud account? If so, why does the Find App on my phone work?

All the best, Florian.

I can not take the find my iPhone for my wife’s iPhone, too! Then I add her iCloud Account next to my Account in OpenHab, but it did not find new things… Only the devices they are linked on family share (with my account).