Better Grbl Support - Error 7

Newly installed latest OctoPrint 1.7.0rc2
Installed Plugin Better Grbl Support
Connected Atomstack A5 via USB
After pressing CONNECT - SerialPort USB0 and Baud 115200
The laser flashes 2 Times than that error appears
Status; Offline after error 7

Connecting to port /dev/ttyUSB0, baudrate 115200
Changing monitoring state from "Opening serial connection" to "Connecting"
Connected to: Serial<id=0x69e99070, open=True>(port='/dev/ttyUSB0', baudrate=115200, bytesize=8, parity='N', stopbits=1, timeout=10.0, xonxoff=False, rtscts=False, dsrdtr=False), starting monitor
Recv: error:7
Changing monitoring state from "Connecting" to "Error"
Send: M112
Send: N1 M112*32
Send: N2 M104 T0 S0*35
Send: N3 M140 S0*102
Changing monitoring state from "Error" to "Offline after error"
Connection closed, closing down monitor