Try Baud-Rate 115200 but keep Transfer Mode Buffered. You can also try enabling DTR, but do only one change at a time then reset connection (right-click Devices button) after each change to test.
Confirm your using the edited device:
In Console Window right-click and select Clear Console, enable Show all then right-click Devices button to reset connection.
After select correct COM port and copy/paste here all the content of the Console Window.
- Alternative:
Read this thread
An test your laser with the following tool: GRBL Serial Diagnostic