stage('Upload to s3') {
  environment {
    AWS_ACCESS_KEY_ID = credentials('AWS_ACCESS_KEY_ID')
    AWS_SECRET_ACCESS_KEY = credentials('AWS_SECRET_ACCESS_KEY')
  }
  steps {
    withAWS(region:'eu-west-1') {
    s3Upload file: 'file.json', bucket: 'bucket', path: 'file.json'
  }
}

java.lang.NullPointerException
	at de.taimos.pipeline.aws.AWSClientFactory.configureBuilder(AWSClientFactory.java:62)
	at de.taimos.pipeline.aws.AWSClientFactory.create(AWSClientFactory.java:55)
	at de.taimos.pipeline.aws.S3UploadStep$RemoteUploader.invoke(S3UploadStep.java:305)
	at de.taimos.pipeline.aws.S3UploadStep$RemoteUploader.invoke(S3UploadStep.java:279)
	at hudson.FilePath$FileCallableWrapper.call(FilePath.java:2750)
	at hudson.remoting.UserRequest.perform(UserRequest.java:208)
	at hudson.remoting.UserRequest.perform(UserRequest.java:54)
	at hudson.remoting.Request$2.run(Request.java:360)
	at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:68)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
	at ......remote call to Default (i-04bddceb619e46ed5)(Native Method)
	at hudson.remoting.Channel.attachCallSiteStackTrace(Channel.java:1654)
	at hudson.remoting.UserResponse.retrieve(UserRequest.java:311)
	at hudson.remoting.Channel.call(Channel.java:905)
	at hudson.FilePath.act(FilePath.java:987)
	at hudson.FilePath.act(FilePath.java:976)
	at de.taimos.pipeline.aws.S3UploadStep$Execution$1.run(S3UploadStep.java:250)
Finished: FAILURE

        AWS_DEFAULT_REGION = 'eu-west-1'