If copy and paste the url into a browser it works.
If I use http Binding I get a warning:
2019-05-08 22:32:37.586 [WARN ] [org.apache.karaf.services.eventadmin] - EventAdmin: Exception during event dispatch [org.osgi.service.event.Event [topic=openhab/command/Lade_Auf_Zu] {item=Lade_Auf_Zu, bridgemarker=true, command=ON, timestamp=1557347557579} | {org.osgi.service.cm.ManagedService, org.osgi.service.event.EventHandler}={service.id=427, service.bundleid=233, service.scope=bundle, event.topics=openhab/*, service.pid=org.openhab.http, component.name=org.openhab.binding.http, component.id=256} | Bundle(org.openhab.binding.http_1.13.0 [233])]
java.util.IllegalFormatConversionException: a != java.util.Date
at java.util.Formatter$FormatSpecifier.failConversion(Formatter.java:4302) ~[?:?]
at java.util.Formatter$FormatSpecifier.printFloat(Formatter.java:2806) ~[?:?]
at java.util.Formatter$FormatSpecifier.print(Formatter.java:2753) ~[?:?]
at java.util.Formatter.format(Formatter.java:2520) ~[?:?]
at java.util.Formatter.format(Formatter.java:2455) ~[?:?]
at java.lang.String.format(String.java:2940) ~[?:?]
at org.openhab.binding.http.internal.HttpBinding.formatAndExecute(HttpBinding.java:267) ~[?:?]
at org.openhab.binding.http.internal.HttpBinding.internalReceiveCommand(HttpBinding.java:130) ~[?:?]
at org.openhab.core.binding.AbstractBinding.receiveCommand(AbstractBinding.java:94) ~[?:?]
at org.openhab.core.events.AbstractEventSubscriber.handleEvent(AbstractEventSubscriber.java:45) ~[?:?]
at org.apache.felix.eventadmin.impl.handler.EventHandlerProxy.sendEvent(EventHandlerProxy.java:415) [3:org.apache.karaf.services.eventadmin:4.2.1]
at org.apache.felix.eventadmin.impl.tasks.HandlerTask.runWithoutBlacklistTiming(HandlerTask.java:82) [3:org.apache.karaf.services.eventadmin:4.2.1]
at org.apache.felix.eventadmin.impl.tasks.SyncDeliverTasks.execute(SyncDeliverTasks.java:104) [3:org.apache.karaf.services.eventadmin:4.2.1]
at org.apache.felix.eventadmin.impl.tasks.AsyncDeliverTasks$TaskExecuter.run(AsyncDeliverTasks.java:166) [3:org.apache.karaf.services.eventadmin:4.2.1]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:?]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:?]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:?]
at java.lang.Thread.run(Thread.java:748) [?:?]