After it downloaded the file, it reports an authentication failure and skips to the next task.
After finishing all downloads it reports that I should check my internet connection.
Just to make sure, I ran update-manager from terminal but still the same problem persisted.
Result of apt-get upgrade:
E: Failed to fetch http://ubuntu.01link.hk/pool/main/a/app-install-data-ubuntu/app-install-data_14.04.1_all.deb Hash Sum mismatch E: Failed to fetch http://ubuntu.01link.hk/pool/main/s/software-center/software-center_13.10-0ubuntu4.1_all.deb Hash Sum mismatch