If sound is only out of one earbud, these instructions are for you.
True Wireless Earbuds can sometimes un-sync from one another requiring a manual reset to enable them to auto sync to one another. This “un-syncing” can happen when only one earbud is being used (single earbud mode) or when a Bluetooth device connects to one of the earbuds prior to the two earbuds syncing to each other when they are removed from the charging case powered on.