SonarScanner MSBuild: Socket Error while uploading report to server

Hi Julien,
Yes, we do have a proxy between the scanner and server.

Note that I also use the same machine for running scans using MSBuild.SonarQube.Runner.exe (version 1.1.0.0) that uploads the report to a different SonarQube server (v5.2). There are no issues connecting to this server.

Below is all I see on the scanner log:

`03:28:36.868 DEBUG: Upload report
 03:28:48.088 INFO: ------------------------------------------------------------------------
 03:28:48.088 INFO: EXECUTION FAILURE
 03:28:48.089 INFO: ------------------------------------------------------------------------
 03:28:48.089 INFO: Total time: 11:44.917s
 03:28:48.145 INFO: Final Memory: 6M/126M
 03:28:48.145 INFO: ------------------------------------------------------------------------
 03:28:48.145 ERROR: Error during SonarQube Scanner execution
 03:28:48.145 ERROR: Fail to request http://xxxxxxxxx:9000/api/ce/submit? 
 projectKey=xxx&projectName=xxxxx
 03:28:48.145 ERROR: Caused by: timeout
 03:28:48.145 ERROR: Caused by: Socket closed
 03:28:48.145 ERROR: Process returned exit code 1
                       The SonarQube Scanner did not complete successfully
 03:28:48.247  Creating a summary markdown file...
 03:28:48.271  Post-processing failed. Exit code: 1`