Apt-get Update "Problem"

Hallo, ich habe unter Ubuntu vor einiger Zeit einen Fehler gemacht und GIMP "falsch installiert". Seitdem wird mir in dem Terminal, wenn ich: sudo apt-get update eingebe: gezeigt.
Wie entferne ich das wieder ich die ganzen Ignorierten GIMP Update Versuche wieder?

sudo apt-get update
OK:1 http://security.ubuntu.com/ubuntu yakkety-security InRelease
OK:2 http://ppa.launchpad.net/appgrid/stable/ubuntu yakkety InRelease
OK:3 http://de.archive.ubuntu.com/ubuntu yakkety InRelease
OK:4 http://de.archive.ubuntu.com/ubuntu yakkety-updates InRelease
OK:5 http://de.archive.ubuntu.com/ubuntu yakkety-backports InRelease
Ign:6 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety InRelease
Ign:7 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety Release
Ign:8 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main amd64 Packages
Ign:9 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main all Packages
Ign:10 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main i386 Packages
Ign:11 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main Translation-en
Ign:12 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main Translation-de_DE
Ign:13 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main Translation-de
Ign:14 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main amd64 DEP-11 Metadata
Ign:15 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main all DEP-11 Metadata
Ign:16 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main DEP-11 64x64 Icons
Ign:8 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main amd64 Packages
Ign:9 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main all Packages
Ign:10 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main i386 Packages
Ign:11 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main Translation-en
Ign:12 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main Translation-de_DE
Ign:13 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main Translation-de
Ign:14 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main amd64 DEP-11 Metadata
Ign:15 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main all DEP-11 Metadata
Ign:16 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main DEP-11 64x64 Icons
Ign:8 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main amd64 Packages
Ign:9 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main all Packages
Ign:10 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main i386 Packages
Ign:11 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main Translation-en
Ign:12 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main Translation-de_DE
Ign:13 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main Translation-de
Ign:14 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main amd64 DEP-11 Metadata
Ign:15 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main all DEP-11 Metadata
Ign:16 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main DEP-11 64x64 Icons
Ign:8 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main amd64 Packages
Ign:9 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main all Packages
Ign:10 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main i386 Packages
Ign:11 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main Translation-en
Ign:12 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main Translation-de_DE
Ign:13 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main Translation-de
Ign:14 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main amd64 DEP-11 Metadata
Ign:15 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main all DEP-11 Metadata
Ign:16 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main DEP-11 64x64 Icons
Ign:8 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main amd64 Packages
Ign:9 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main all Packages
Ign:10 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main i386 Packages
Ign:11 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main Translation-en
Ign:12 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main Translation-de_DE
Ign:13 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main Translation-de
Ign:14 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main amd64 DEP-11 Metadata
Ign:15 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main all DEP-11 Metadata
Ign:16 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main DEP-11 64x64 Icons
Fehl:8 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main amd64 Packages
  404  Not Found
Ign:9 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main all Packages
Ign:10 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main i386 Packages
Ign:11 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main Translation-en
Ign:12 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main Translation-de_DE
Ign:13 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main Translation-de
Ign:14 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main amd64 DEP-11 Metadata
Ign:15 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main all DEP-11 Metadata
Ign:16 https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety/main DEP-11 64x64 Icons
Paketlisten werden gelesen... Fertig
W: The repository 'https://download.gimp.org/mirror/pub/gimp/v2.8 yakkety Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure( manpage for repository creation and user configuration details.
E: Fehlschlag beim Holen von https://download.gimp.org/mirror/pub/gimp/v2.8/dists/yakkety/main/binary-amd64/Packages  404  Not Found
E: Einige Indexdateien konnten nicht heruntergeladen werden. Sie wurden ignoriert oder alte an ihrer Stelle benutzt.