Errors/Chain errors
GrandpaChangeDelayMustBeZero
Check the argument values against the operation schema
schedule_grandpa_change was given a nonzero in_blocks delay. GRANDPA authority changes submitted through AdminUtils must activate at the end of the current block so the authority set and its set ID remain consistent. Pass in_blocks=0.
Declared by the AdminUtils pallet; it classifies to the semantic code invalid_argument.
Declared at pallets/admin-utils/src/lib.rs#L182.
Remediation
Check the argument values against the operation schema
The same explanation is available in the terminal: btcli explain GrandpaChangeDelayMustBeZero.