J’ai eu le même problème et retirer la batterie des buds et la remettre l’a réglé comme proposé ici 
Problems with Fairbuds - pairing, factory reset, no sound in right ear
Hello Fairbuds owners,
I bought my earbuds in December 2026. I use them not so often and at the past few days I’ve been experiencing the same problem discussed here. As I count here, I am the 12th user with this problem:
The left earbud no longer works, the battery indicator in the app shows 10%. It also won’t charge.
It seems that Fairphone hasn’t found a solution in the last year and a half and is still selling this affected series.
I’m going to open a support ticket and send the Fairbuds back for repair. Let’s see if the repair center finds anything and has a solution, or if they can’t find anything wrong they send them back unrepaired. An exchange would also be bad, as I suspect that the new ones will also develop the problem sooner or later.
So, I got my Fairbuds back from repair. They couldn’t find anything wrong.
After that, I reread all the information about the Fairbuds and came across the following statement:
The Fairbuds charge when connected with a standard USB-C cable.
We recommend a power output of 5V - 0.5A.
I looked among my chargers and found a charger with fix 5V and max. 2A.
Then I loaded the box and earbuds for 2h, open the box, put the earbuds out and making a new pairing. Then I started the app and see after a while (ca. 10-15s) on both earbuds 100%.
Then putting the left earbud back in the box and close the box. After ca. 8s the app says 10% to the left earbud. Therefore, I believe that a 10% display indicates that the earphone is switched off.
I tried the same thing with the right earbud, but this time the Bluetooth connection was interrupted with right earbud in and left earbud out when I closed the box.
During my further tests, I experienced strange effects in the app, and it could no longer find the Fairbuds.
All other problems are described here. And in my opinion, they are never due to defective hardware.
Hello,
So, I can now confirm that my left earbud runs out of battery after about two days in the case.
Although the case displays a green light, indicating a full charge when the button is pressed, I can only bring the earbuds back to life (and charge them to 100%) by reconnecting a 5V charger to the case.
However, after two days inside the case, the left earbud is drained again.
I have opened a support ticket and waiting for an answer.