logstash https output error

config:
input {
  file {
    type => "mc-access-log"
    path => ["/var/log/mc-access.log"]
  }
}

output {
  http {
    type => "mc-access-log"
    format => "json"
    http_method => "post"
    headers => ["Authorization", "Basic <base64 encoded creds>"]
    url => "https://example.com/mc/accesslog/event"
  }
}

Exception:
{:message=>"Unhandled exception", :request=><FTW::Request(@4040) @protocol="https" @body="{\"@source\":\"file://<***>\",\"@tags\":[],\"@fields\":{},\"@timestamp\":\"2013-01-27T00:15:47.935Z\",\"@source_host\":\"<***>\",\"@source_path\":\"<***>\",\"@message\":\"<***>\",\"@type\":\"<***>\"}" @method="POST" @headers=FTW::HTTP::Headers <{"host"=>"<***>", "connection"=>"keep-alive", "authorization"=>"<***>", "content-type"=>"application/json", "content-length"=>378}> @logger=#<Cabin::Channel:0x3d63b102 @subscriber_lock=#<Mutex:0x5bfa19ca>, @metrics=#<Cabin::Metrics:0xb34bf3 @channel=#<Cabin::Channel:0x3d63b102 ...>, @metrics={}, @metrics_lock=#<Mutex:0x7b3f3ee0>>, @data={}, @subscribers={}, @level=:info> @version=1.1 @request_uri="<***>" @port=443 >, :response=>#<FTW::Response:0xdd9a6ac @headers=FTW::HTTP::Headers <{"server"=>"nginx", "date"=>"Sun, 27 Jan 2013 00:15:47 GMT", "content-type"=>"text/plain", "content-length"=>"2", "connection"=>"close", "x-powered-by"=>"Express"}>, @body=<FTW::Connection(@4042) @destinations=["<***>:443"] @connected=true @remote_address="<***>" @secure=true >, @status=200, @logger=#<Cabin::Channel:0x3d63b102 @subscriber_lock=#<Mutex:0x5bfa19ca>, @metrics=#<Cabin::Metrics:0xb34bf3 @channel=#<Cabin::Channel:0x3d63b102 ...>, @metrics={}, @metrics_lock=#<Mutex:0x7b3f3ee0>>, @data={}, @subscribers={}, @level=:info>, @reason="OK", @version=1.1>, :exception=>#<EOFError: End of file reached>, :stacktrace=>["org/jruby/ext/openssl/SSLSocket.java:634:in `sysread'", "jar:file:/opt/logstash/logstash-1.1.9-monolithic.jar!/gems/ftw-0.0.26/lib/ftw/connection.rb:230:in `read'", "jar:file:/opt/logstash/logstash-1.1.9-monolithic.jar!/gems/ftw-0.0.26/lib/ftw/protocol.rb:142:in `read_http_body_length'", "jar:file:/opt/logstash/logstash-1.1.9-monolithic.jar!/gems/ftw-0.0.26/lib/ftw/protocol.rb:108:in `read_http_body'", "jar:file:/opt/logstash/logstash-1.1.9-monolithic.jar!/gems/ftw-0.0.26/lib/ftw/protocol.rb:133:in `read_body'", "file:/opt/logstash/logstash-1.1.9-monolithic.jar!/logstash/outputs/http.rb:112:in `receive'", "file:/opt/logstash/logstash-1.1.9-monolithic.jar!/logstash/outputs/base.rb:55:in `handle'", "file:/opt/logstash/logstash-1.1.9-monolithic.jar!/logstash/agent.rb:758:in `run_output'", "file:/opt/logstash/logstash-1.1.9-monolithic.jar!/logstash/agent.rb:379:in `start_output'"], :level=>:warn}