When subscribing to operations using the Cumulocity java-client I am getting: com.cumulocity.sdk.client.SDKException: unable to subscribe Client: fwy51ui5s1crhtn1p1qkybrl2me2 on Channel:/meta/subsc...

I have a Methode from an API. It returns a promise which resolves to an $ctrl(?) object. This objects should contain a measurement and will be updated whenever it receive a new data. getMeasureme...