NotOwner

Sign with the key or origin that owns the target object, then retry

Only the account that opened the multisig operation (its depositor) may cancel it or adjust its deposit. Compare the sender against the depositor field stored in the Multisigs entry for this call hash.

Declared by the Multisig pallet; it classifies to the semantic code not_authorized.

Remediation

Sign with the key or origin that owns the target object, then retry

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