I am on ubuntu 18.04 LTS. Right after I turn on Ubuntu, a red warning like icon appears in the gnome indicator which tells
The update information is outdated. This may be caused by network problems or by a repository that is no longer available. Please update manually by selecting 'Show updates' from the indicator menu, and watching for any failing repositories.
I clicked on Show updates. It just tells me Everything is up to date. Nothing is happening.