ChangePending

The object or state already exists; treat the goal as met or pick a different target

A GRANDPA authority-set change has already been signalled and is still pending, so a new change cannot be scheduled. Check the Grandpa PendingChange and State storage and wait for the pending change to be applied first.

Declared by the Grandpa pallet; it classifies to the semantic code already_exists.

Remediation

The object or state already exists; treat the goal as met or pick a different target

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