## TL;DR
3 seconds is Lambda's default timeout, not a verdict on your code: the function (or something it calls) simply needs longer. Raise the timeout toward what the workload needs and fix the slow downstream call. Timeouts stop once the budget fits reality.

## Error
```text
aws lambda: Task timed out after 3.00 seconds
```

## Steps
1. Confirm the configured timeout: check the function's configuration. Expected: it is still the 3-second default, which explains the exact message.
2. Find what burned the time: check CloudWatch logs for the REPORT line's duration and billed duration, and look for slow downstream calls (database, API, VPC cold start). Expected: one slow dependency identified.
3. Raise the timeout to a sane value for the workload (Lambda allows up to 15 minutes). Expected: the function gets room to finish.
4. Fix the underlying slowness: add connection reuse, move the function out of a cold VPC path if ENI attachment dominates, or cache the slow call. Expected: duration drops well under the new timeout.
5. Re-run and check the REPORT line. Expected: no timeout, with duration comfortably below the configured limit.

## When to use
- Lambda fails with "Task timed out after 3.00 seconds"
- New functions deployed with default settings
- Functions that call slow external services

## When not to use
- Out-of-memory kills (memory, not time)
- Packaging or runtime import errors

## Tool compatibility
- AWS Lambda timeout configuration (max 15 minutes); CloudWatch Logs REPORT lines

## Variant phrasings
### lambda timeout default 3 seconds
Raise it; almost no real workload fits the default once network calls are involved.

### lambda slow cold start vpc
VPC-attached functions pay ENI setup on cold starts; raise the timeout and consider provisioned concurrency.

## Why it happens
Lambda defaults to 3 seconds because the original use case was tiny event handlers. Modern functions calling databases and APIs routinely need tens of seconds, so the default is almost always the first thing to change on a new function.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_sRY8tNV_RiplNyAZTQCdCA