java.lang.NullPointerException
	at org.jenkinsci.plugins.publishoverdropbox.domain.JsonObjectRequest.getProxy(JsonObjectRequest.java:209)
	at org.jenkinsci.plugins.publishoverdropbox.domain.JsonObjectRequest.openConnection(JsonObjectRequest.java:200)
	at org.jenkinsci.plugins.publishoverdropbox.domain.JsonObjectRequest.execute(JsonObjectRequest.java:146)
	at org.jenkinsci.plugins.publishoverdropbox.domain.DropboxV2.retrieveAccountInfo(DropboxV2.java:142)
	at org.jenkinsci.plugins.publishoverdropbox.domain.DropboxV2.connect(DropboxV2.java:121)
	at org.jenkinsci.plugins.publishoverdropbox.domain.DropboxClient.connect(DropboxClient.java:118)
	at org.jenkinsci.plugins.publishoverdropbox.impl.DropboxHostConfiguration.connect(DropboxHostConfiguration.java:112)
	at org.jenkinsci.plugins.publishoverdropbox.impl.DropboxHostConfiguration.init(DropboxHostConfiguration.java:100)
	at org.jenkinsci.plugins.publishoverdropbox.impl.DropboxHostConfiguration.createClient(DropboxHostConfiguration.java:83)
	at org.jenkinsci.plugins.publishoverdropbox.impl.DropboxHostConfiguration.createClient(DropboxHostConfiguration.java:47)
	at jenkins.plugins.publish_over.BPHostConfiguration.createClient(BPHostConfiguration.java:96)
	at jenkins.plugins.publish_over.BapPublisher$Performer.perform(BapPublisher.java:229)
	at jenkins.plugins.publish_over.BapPublisher$Performer.access$000(BapPublisher.java:205)
	at jenkins.plugins.publish_over.BapPublisher.perform(BapPublisher.java:158)
	at jenkins.plugins.publish_over.BPCallablePublisher.invoke(BPCallablePublisher.java:65)
	at jenkins.plugins.publish_over.BPCallablePublisher.invoke(BPCallablePublisher.java:38)
	at hudson.FilePath$FileCallableWrapper.call(FilePath.java:2749)
	at hudson.remoting.UserRequest.perform(UserRequest.java:153)
	at hudson.remoting.UserRequest.perform(UserRequest.java:50)
	at hudson.remoting.Request$2.run(Request.java:336)
	at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:68)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)
Caused: jenkins.plugins.publish_over.BapPublisherException: Exception when publishing, exception message [null]
	at jenkins.plugins.publish_over.BPCallablePublisher.invoke(BPCallablePublisher.java:69)
	at jenkins.plugins.publish_over.BPCallablePublisher.invoke(BPCallablePublisher.java:38)
	at hudson.FilePath$FileCallableWrapper.call(FilePath.java:2749)
	at hudson.remoting.UserRequest.perform(UserRequest.java:153)
	at hudson.remoting.UserRequest.perform(UserRequest.java:50)
	at hudson.remoting.Request$2.run(Request.java:336)
	at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:68)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)
	at ......remote call to j-worker01(Native Method)
	at hudson.remoting.Channel.attachCallSiteStackTrace(Channel.java:1545)
	at hudson.remoting.UserResponse.retrieve(UserRequest.java:253)
	at hudson.remoting.Channel.call(Channel.java:830)
	at hudson.FilePath.act(FilePath.java:987)
	at hudson.FilePath.act(FilePath.java:976)
	at jenkins.plugins.publish_over.BPInstanceConfig.perform(BPInstanceConfig.java:141)
	at org.jenkinsci.plugins.publishoverdropbox.impl.step.DropboxPublishStepExecution$1.run(DropboxPublishStepExecution.java:87)
	at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
	at java.util.concurrent.FutureTask.run(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)