Cant install via Ubuntu Software- "apt transaction returned result exit-failed"

I'm using 17.04 ( Clean Install ), and as far as I remember, every try to install any sofware- it fails with that error code.

I tried sudo apt-get update && apt-get upgrade and problem persists.

any idea why?

edit: Using software Updater gave this result :

edit : output of update

guy@LG-LAPTOP:~$ sudo apt-get update && apt-get upgrade
[sudo] password for guy: 
Ign:1 http://il.archive.ubuntu.com/ubuntu zesty InRelease
Ign:2 http://il.archive.ubuntu.com/ubuntu zesty-updates InRelease              
Ign:3 http://il.archive.ubuntu.com/ubuntu zesty-backports InRelease            
Err:4 http://il.archive.ubuntu.com/ubuntu zesty Release                        
  503  Service Unavailable
Get:5 http://security.ubuntu.com/ubuntu zesty-security InRelease [89.2 kB]     
Err:6 http://il.archive.ubuntu.com/ubuntu zesty-updates Release                
  503  Service Unavailable
Get:7 http://archive.canonical.com/ubuntu zesty InRelease [10.2 kB]            
Err:8 http://il.archive.ubuntu.com/ubuntu zesty-backports Release              
  503  Service Unavailable
Get:9 http://archive.canonical.com/ubuntu zesty/partner Sources [1,416 B]      
Get:10 http://archive.canonical.com/ubuntu zesty/partner amd64 Packages [1,616 B]
Get:11 http://archive.canonical.com/ubuntu zesty/partner i386 Packages [1,612 B]
Get:12 http://archive.canonical.com/ubuntu zesty/partner Translation-en [708 B]
Get:13 http://security.ubuntu.com/ubuntu zesty-security/main amd64 DEP-11 Metadata [11.7 kB]
Get:14 http://security.ubuntu.com/ubuntu zesty-security/main DEP-11 64x64 Icons [9,219 B]
Get:15 http://security.ubuntu.com/ubuntu zesty-security/universe amd64 DEP-11 Metadata [14.4 kB]
Get:16 http://security.ubuntu.com/ubuntu zesty-security/universe DEP-11 64x64 Icons [31.0 kB]
Reading package lists... Done                                         
E: The repository 'http://il.archive.ubuntu.com/ubuntu zesty Release' does no longer have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http://il.archive.ubuntu.com/ubuntu zesty-updates Release' does no longer have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http://il.archive.ubuntu.com/ubuntu zesty-backports Release' does no longer have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
guy@LG-LAPTOP:~$ 

output of apt get

guy@LG-LAPTOP:~$ sudo apt-get install putty
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following additional packages will be installed:
  putty-tools
Suggested packages:
  putty-doc
The following NEW packages will be installed:
  putty putty-tools
0 upgraded, 2 newly installed, 0 to remove and 0 not upgraded.
Need to get 661 kB of archives.
After this operation, 2,713 kB of additional disk space will be used.
Do you want to continue? [Y/n] 
Err:1 http://il.archive.ubuntu.com/ubuntu zesty/universe amd64 putty-tools amd64 0.67-3
  503  Service Unavailable
Err:2 http://il.archive.ubuntu.com/ubuntu zesty/universe amd64 putty amd64 0.67-3
  503  Service Unavailable
E: Failed to fetch http://il.archive.ubuntu.com/ubuntu/pool/universe/p/putty/putty-tools_0.67-3_amd64.deb  503  Service Unavailable
E: Failed to fetch http://il.archive.ubuntu.com/ubuntu/pool/universe/p/putty/putty_0.67-3_amd64.deb  503  Service Unavailable
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
guy@LG-LAPTOP:~$ 

You're having problems with your software sources servers. Change it from the Software Sources app. You can get to it by:

• (Click) the Gear Icon at the top left
• System Settings
• Software & Updates
• (click the tab) Ubuntu Software
• Choose a different server from the Download Dropdown

You'll get the best server if you choose Other, then click Select Best Server. On that option, the system will run tests and match you with a mirror server with the best performance for your location.