That ‘Invalid Audio Setup’ error is almost certainly a sample rate mismatch rather than a hardware failure. Soundjack is notoriously strict about requiring 48kHz; if your OS or mixer is set to 44.1kHz, the software will reject the input even if the device is recognized.
I have encountered similar synchronization challenges when handling real-time data streams in my professional work. At https://topdevs.org/services/web-development where we build high-performance web solutions, ensuring precise protocol alignment is critical for stability. Try forcing your input device to 48kHz in your system’s sound control panel before launching the app; that should turn the VU meter green.