Errors/Chain errors
ThresholdTooHigh
Check the argument values against the operation schema
The safe multisig threshold exceeds the full signatory count, including the sender. Use a threshold no greater than the number of distinct group members.
Declared by the Multisig pallet; it classifies to the semantic code invalid_argument.
Remediation
Check the argument values against the operation schema
The same explanation is available in the terminal: btcli explain ThresholdTooHigh.