The narration engine fails to start and the message now shows an exit code or a signal. What does it mean?

From version 1.9.5, when the narration engine cannot start, the message includes how it stopped (an exit code or a signal such as SIGKILL) and the error line it printed, for example "exit code 1: Error: Could not load ...". Send that message to support as it is; it points straight at the cause. Common ones: a security or antivirus tool stopping the engine's helper process (usually a signal), or a broken engine download (delete and re-download the engine from Settings, BookyAI Audio).