Hi. I really doubt this is a drakma issue but Amazon has been of no help. I've written a Lisp interface to the EC2 Query API (CL-EC2<http://common-lisp.net/project/cl-ec2/>); it uses Drakma has its http client. All of the implemented API calls work just fine with the exception of the Cloudwatch ListMetrics call, which for some reason began failing this week. Amazon's cloudwatch scratchpad tool fails now also with the same error, but I tried the python boto library and it works fine, as does the Amazon command-line tool mon-list-metrics. Here's the header output: SIERRA(29): (ec2:with-header-stream () (cw:list-metrics)) GET /?AWSAccessKeyId=<our access key>?Action=ListMetrics&SignatureMethod=HmacSHA256&SignatureVersion=2&Timestamp=2010-02-24T20%3A46%3A25Z&Version=2009-05-15&Signature=BHAB8OAeGU6IRp6Ki%2BDuEKM9%2FOiKKOSu%2FGntICOotqI%3D HTTP/1.1 Host: monitoring.amazonaws.com User-Agent: Drakma/1.1.0 (SBCL 1.0.30; Linux; 2.6.30.10-105.2.16.fc11.x86_64; http://weitz.de/drakma/) Accept: */* Connection: close HTTP/1.1 400 Bad Request x-amzn-RequestId: ac7304ba-2185-11df-a0eb-cd40a3846a7b Content-Type: text/xml Content-Length: 270 Date: Wed, 24 Feb 2010 20:46:25 GMT And here's the condition as reported by our library: Amazon EC2 Error: Bad Request: status: 400 uri: http://monitoring.amazonaws.com?AWSAccessKeyId=<our access key>&Action=ListMetrics&SignatureMethod=HmacSHA256&SignatureVersion=2&Timestamp=2010-02-24T20%3A46%3A25Z&Version=2009-05-15&Signature=BHAB8OAeGU6IRp6Ki%2BDuEKM9%2FOiKKOSu%2FGntICOotqI%3D headers: ((X-AMZN-REQUESTID . ac7304ba-2185-11df-a0eb-cd40a3846a7b) (CONTENT-TYPE . text/xml) (CONTENT-LENGTH . 270) (DATE . Wed, 24 Feb 2010 20:46:25 GMT)) body: ((ErrorResponse xmlns http://monitoring.amazonaws.com/doc/2009-05-15/) (Error (Type Sender) (Code DelegationFailure) (Message Malformed token)) (RequestId ac7304ba-2185-11df-a0eb-cd40a3846a7b)) [Condition of type EC2:EC2-ERROR] I'm just looking for some ideas, so forgive me if I've bothered anyone. What the hell is a DelegationFailure anyway? Sorry to trouble you folks. Thanks. -- david -- And now these three remain: faith, hope, and love. But the greatest of these is love. -- 1 Corinthians 13:13 To truly engage with how the world is, our hearts are going to be broken again and again. -- Rob Bell, "Velvet Elvis, Repainting the Christian Faith" To produce without possessing, to work without expecting, to enlarge without usurping. This is the supreme virtue. -- Lao-Tzu