Huawei Mate 10 - music per aux (or type c) is no longer possible?

Since the update of the last days the music play in the car does not work anymore. Have already tried different type c to aux adapter and also different aux cable. The boxes in the car also work perfectly. The connection of the cable also recognizes the mobile phone. The music is also played, but you just hear nothing… Does anyone have a tip for me?

Have you already adjusted the volume on both devices, ie smartphone and system?

Does the system work in the car with other players, e.g. Other smartphone or MP3 player? Does your phone play music on other speakers or headphones? You should be connected to Aux via Aux or USB Type-C?