@NDOUR Ndeye Dioma Thanks for reaching out. Can you help us with what kind of FIDO key you have ?
Mostly in scenarios if you have a FIDO U2F security key (Universal second factor), there is no way to reset it. You can only unregister it from service manually and then re-register it.
You can do that from your Security Info page : https://mysignins.microsoft.com/security-info,
If not, your admin can do it for you : https://learn.microsoft.com/en-us/azure/active-directory/authentication/howto-authentication-passwordless-security-key#disable-a-key
You will need to add it again and create a new key.
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