Inexplicable Error in the karaf console

Every few minutes I get the following error message:

Exception in thread “upnp-async-240” java.lang.IllegalArgumentException: Invalid URI host: null (authority: null)
at org.eclipse.jetty.client.HttpClient.checkHost(HttpClient.java:521)
at org.eclipse.jetty.client.HttpClient.newHttpRequest(HttpClient.java:506)
at org.eclipse.jetty.client.HttpClient.newRequest(HttpClient.java:464)
at org.jupnp.transport.impl.jetty.JettyStreamClientImpl.createRequest(JettyStreamClientImpl.java:106)
at org.jupnp.transport.impl.jetty.JettyStreamClientImpl.createRequest(JettyStreamClientImpl.java:1)
at org.jupnp.transport.spi.AbstractStreamClient.sendRequest(AbstractStreamClient.java:87)
at org.jupnp.transport.RouterImpl.send(RouterImpl.java:327)
at org.jupnp.protocol.RetrieveRemoteDescriptors.describeService(RetrieveRemoteDescriptors.java:325)
at org.jupnp.protocol.RetrieveRemoteDescriptors.describeServices(RetrieveRemoteDescriptors.java:263)
at org.jupnp.protocol.RetrieveRemoteDescriptors.describe(RetrieveRemoteDescriptors.java:205)
at org.jupnp.protocol.RetrieveRemoteDescriptors.describe(RetrieveRemoteDescriptors.java:184)
at org.jupnp.protocol.RetrieveRemoteDescriptors.run(RetrieveRemoteDescriptors.java:104)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:829)

Every thing works fine, but the message is disturbing. Any idea what could be the reason for this message. I use OH 3.2.0 on Win10 but got the message before on the RASPI to.