Someone over in this bug (https://bugs.launchpad.net/ubuntu/+source/wget/+bug/232469) found the problem. The environment variable no_proxy has a trailing comma which it should not. Once you remove that, downloads through the proxy started working. I don't know whether this is the same problem that other people on this bug have been experiencing though.
Someone over in this bug (https:/ /bugs.launchpad .net/ubuntu/ +source/ wget/+bug/ 232469) found the problem. The environment variable no_proxy has a trailing comma which it should not. Once you remove that, downloads through the proxy started working. I don't know whether this is the same problem that other people on this bug have been experiencing though.