not output sound, I can hear it by headphones

[Ahmed El Faleh]

I make sure that the speakers is the default output.

but usually i hear by headphones no speakers

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: pulseaudio 1:8.0-0ubuntu3.1
ProcVersionSignature: Ubuntu 4.4.0-59.80-generic 4.4.35
Uname: Linux 4.4.0-59-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.20.1-0ubuntu2.4
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: elfaleh 1797 F.... pulseaudio
Date: Fri May 12 22:49:56 2017
InstallationDate: Installed on 2017-01-04 (128 days ago)
InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon.
SourcePackage: pulseaudio
Symptom: audio
UpgradeStatus: Upgraded to xenial on 2017-01-04 (128 days ago)
dmi.bios.date: 07/31/2009
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A01
dmi.board.name: 047MWF
dmi.board.vendor: Dell Inc.
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA01:bd07/31/2009:svnDellInc.:pnVostro1015:pvr:rvnDellInc.:rn047MWF:rvr:cvnDellInc.:ct8:cvr:
dmi.product.name: Vostro 1015
dmi.sys.vendor: Dell Inc.