TransferFailed

A balance transfer performed during the contract call failed, most likely because the sender lacks enough free balance. Check the transferring account's free balance against the value being sent, accounting for the existential deposit.

Declared by the Contracts pallet; it classifies to the semantic code insufficient_balance.

Remediation

Fund the signing account or reduce the amount; check with btcli wallet balance

The same explanation is available in the terminal: btcli explain TransferFailed.