The JBL Clip 3 and 4, as well as the Flip 3, 4, and 5 all use these buttons to reset. Release the buttons when the status light turns off.

Once you reset your JBL speaker, re-pair it to use it again.

This is the key combination for resetting a JBL Charge and Charge 3 Speaker. [1] X Research source

This method works for JBL Charge 4, the JBL Xtreme, Boombox, and Go 2 speakers.

Release these buttons after about 10-15 seconds or after the speaker turns off.