> ## Documentation Index
> Fetch the complete documentation index at: https://docs.sqd.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# E1004

> Fork handling — Portal contract violation

The portal delivered a `canonicalBlocks` set whose highest block is below the target's persisted
cursor. Rows above it would survive the fork rollback and corrupt the new chain, so the pipe refuses
to proceed. Any target that tracks a cursor can raise this.

**Fix** — none in user code; please
[report it as a bug](https://github.com/subsquid-labs/pipes-sdk/issues) against the portal contract.