iPhone X problems with Audiolab M-DAC Mini

Connecting an M-DAC Mini to my iPhone X via usb or Bluetooth the playback stops with an error message popping up. The error message however clears so quickly that it is impossible to read from start to Finish but I do see the words Hardware and Software mentioned!. Playing the Apple Music app via Bluetooth works ok also connecting to my MacBook 12" via USB-C also appears to work. FYI streaming from a Nucleus.