# 101004: Lock invalidated by concurrent request

Identifier: `lock_invalidated_by_concurrent_request`



A lock that appeared to be acquired was invalidated because another member requested the same lock concurrently and now holds it.

## What you should do

Treat the [lock](https://ably.com/docs/spaces/locking.md) as not held by you and handle losing it, for example by releasing the component you were editing. When two members request the same lock at nearly the same time, only one can win, so your application should be prepared for a request that briefly looked successful to be invalidated.

## Why it happens

Another member requested the same lock concurrently and now holds it, which invalidated this member's request even though it had appeared to succeed. Only one member can hold a lock, so a concurrent request is resolved in favor of a single winner.

## What you'll see

The error is reported with code 101004 and HTTP status 400. The message is `lock was invalidated by a concurrent lock request which now holds the lock`.