please notice following missing/wrong information in the UserGuide (Melody V7.x).
The step values of conn_attempt_timeout seem to be 0,1s / 100ms. ( UserGuide says 0.625ms)
With the default value of 100 a OPEN attempt to a not available device lasted 10s until the module send a OPEN_ERROR BLE.
It says “to be defined” in the UserGuide, but the current defintion is lightyears away from current implementation