Apt-get cannot be downloaded, and some URLs NotFound solve the problem.

Apt-get cannot be downloaded, and some web sites NotFound solve the problem a few days ago. due to the needs of scientific research, ubuntu11.04 was installed in the virtual machine, but some errors were always prompted when downloading and installing the software. The error message is as follows. W: cannot download http://archive.ubuntu.com /... apt-get cannot be downloaded, and some Web sites Not Found solve the problem a few days ago. due to scientific research needs, ubuntu11.04 was installed in the virtual machine, but some errors were always prompted when downloading and installing the software. The error message is as follows. W: cannot download http://archive.ubuntu.com/ubuntu/dists/jaunty-security/multiverse/source/Sources 404 Not Found [IP: 91.189.88.46 80] E. I found a lot of information on the Internet, saying that there was a problem with the source. I found the source of the corresponding version as prompted and replaced it, but the same error was still prompted. Finally, copy the source on my host (ubuntu-12.04) directly to the virtual machine, everything is OK. Run the following command on ubuntu11: 11, vi/etc/apt/source. list // execute the same command on the host and copy the content to the VM file 22, apt-get update