Cannot charge the battery

Try the following:

• The headset may be set in the charging case incorrectly. Insert the headset's left (L) and right (R) units into the corresponding places in the charging case, and then firmly close the case's cover.
• The charging case's battery may have run out. Charge it by connecting the supplied USB Type-C cable to the charging case's USB port.
• If the terminals are dirty, there may be contact failures.
  • Try setting the headset in the charging case and taking it out a few times.
  • Wipe the headset's and the charging case's terminals with a soft, dry cloth.
• A safeguard may be running that blocks charging. If either the headset's or the charging case's indicators flash red 2 times repeatedly while charging, leave the headset and charging case at room temperature for 1 or 2 hours, and then charge them somewhere that is between 5 ℃ and 35 ℃.