apt-get update Could not resolve 'http.kali.org'

apt-get update
Err http://security.kali.org kali/updates Release.gpg
Could not resolve 'security.kali.org'
Err http://http.kali.org kali-dev Release.gpg
Could not resolve 'http.kali.org'
Err http://http.kali.org kali Release.gpg
Could not resolve 'http.kali.org'
Reading package lists... Done
W: Failed to fetch http://http.kali.org/kali/dists/kali-dev/Release.gpg Could not resolve 'http.kali.org'

W: Failed to fetch http://http.kali.org/kali/dists/kali/Release.gpg Could not resolve 'http.kali.org'

W: Failed to fetch http://security.kali.org/kali-securi...es/Release.gpg Could not resolve 'security.kali.org'

W: Some index files failed to download. They have been ignored, or old ones used instead.

i try to fixed it any way that i googling or find in this forum but it not success help me please..
ps. i can ping to http.kali.org
srry about my bad english :p

I also having same problem..

Most of this issuses are no network connected or wrong proxy settings. Check your network or default all proxy settings. Another reason is sources.list, default it as official also.

Im having issues with it also but when i use vpn it worked perfect.