nothing works for apt update Ign Error !
if nothing works for your problem just open a terminal and run this command :
sudo nano /etc/apt/apt.conf
and write this line of code inside of apt.conf file :
Acquire::http::Proxy "http://yourproxyaddress:proxyport";
go in software and updates . then click on select-box "download from" , click on "other ..." . and click on select best server in popped up window . wait to test complete .
enter this command:
code /etc/apt/sources.list.d/
and open ubuntu.sources
file .
comment this section:
# Types: deb
# URIs: http://security.ubuntu.com/ubuntu/
# Suites: noble-security
# Components: main restricted universe multiverse
# Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg