An error occurred (NoSuchKey) when calling the GetObject operation: The specified key does not exist. code example

Example: An error occurred (NoSuchKey) when calling the GetObject operation: The specified key does not exist.

#An error occurred (NoSuchKey) when calling the GetObject operation: The specified key does not exist.
Maybe you are hardcoding filename into your aws lambda function.
# you are try to access file_name like this s3_file_name ='test2.csv'
# But it's saved into S3 bucket like this s3_file_name ='test.csv'
You need to call exact file_name into your aws lambda code.