Search CloudWatch logs for: timed "Task timed out after"
https://aws.amazon.com/premiumsupport/knowledge-center/lambda-sqs-scaling/
Search CloudWatch logs for: Error
Example filter for CW Logs Insights:
fields @timestamp, @message
| filter @message like /Error/
| limit 20
Other errors: https://aws.amazon.com/premiumsupport/knowledge-center/lambda-troubleshoot-function-failures/