Underflow

A checked subtraction underflowed in crowdloan accounting, e.g. raised exceeding cap when computing remaining room, or a contributor count decrement, indicating inconsistent state. Inspect the Crowdloans and Contributions entries for the crowdloan_id.

Declared by the Crowdloan pallet; it classifies to the semantic code internal.

Remediation

A chain-side invariant failed; nothing to fix client-side — report it if it persists

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