401 Unauthorized when the s3_start_transfer Lambda tries to run

401 Unauthorized when the s3_start_transfer Lambda tries to run

We have an s3_start_transfer Lambda which is meant to notice uploads to the transfer source bucket, and trigger a new transfer process in Archivematica. If that's not working, and you see this in the CloudWatch logs:

Response: <Response [401]>

it might be a sign that the Lambda has bad credentials for the Archivematica API. These are kept in Parameter Store, then injected into the Lambda by Terraform (see transfer_lambda.tf).

Verify the credentials are correct, or create and store new API keys as necessary.