When the earbuds are not coupled properly, the earbud battery indicator light will flash red. To recouple them, remove the earbuds from the charging case and insert them again. Then, touch and hold both earbuds’ touchpads for seven seconds or more while they are in the case. The earbud battery indicator light will flash green and return to its initial color.  The earbuds will be coupled, and then you can try wearing them again.