I have encountered a similar problem and here's my solution;
# While the headphones are turned 'on' press and hold vol + and vol - at the same time , a blue light flashes.
# Turn off the headphones and turn them on again, now instead of a red, you will see a combination of flashing blue and red lights , this means it's in pairing mode
# Forget your headphones from previously connected devices list on your tab/phone/etc
# Re pair it
# Done.