Have you accidentally transferred your bitcoin to an invalid address? Did your bitcoins not arrive at the receiver’s address? Have you forgotten your password, or only remember some of it? Is your private key no longer working? Is your wallet “watch only”? Did your mobile phone break, is your computer not starting, or does your storage have a defect (USB drive, hard disk, etc.) and your Bitcoins are gone? Does your wallet software have a defect, have you deleted data accidentally, or is your system infected by a virus? Did you transfer bitcoin cash to a bitcoin wallet or vice versa, and are you not able to access your funds anymore?