Failed to successfully establish a connection to the leader. (http status: 502)

[1309893329]

My batch submission prompted 502 errors, but the release was successful!!，why???

The following is the API I wrote：
@RequestLine("PUT /v2/apps/{app_id}?force=true")
@headers(HeaderUtils.MARATHON_API_SOURCE_HEADER)
void forceUpdateApp(@ Named("app_id") String appId, App app) throws MarathonException;

Failed to successfully establish a connection to the leader. (http status: 502)
at com.mesosphere.marathon.client.MarathonClient$MarathonErrorDecoder.decode(MarathonClient.java:28)
at feign.MethodHandler$SynchronousMethodHandler.executeAndDecode(MethodHandler.java:154)
at feign.MethodHandler$SynchronousMethodHandler.invoke(MethodHandler.java:105)
at feign.ReflectiveFeign$FeignInvocationHandler.invoke(ReflectiveFeign.java:87)
at com.sun.proxy.$Proxy90.forceUpdateApp(Unknown Source)