# Turn on the JBL Flip 4. Press and hold the power button until it lights up. ...
# Wait for the Power Up Sound. The speaker makes a rising electric guitar strum sound when it powers up. ... which you are not hearing… so give it a few seconds after start up.
# Press the Volume UP and Play-Pause Buttons Together. ...
# Check that your JBL Flip 4 Did Reset. ...
# Done! Try reconnecting.
If doesn't work try this
[guide|39863]