It looks like you are using an old version of lego. Could you please update it to the latest version (currently 2.x) and try to renew the certificate again? Remember to add the
renew argument at the end of your command because it looks like you didn't provide it from what you posted.
You can download latest lego version by running the commands below
rm -rf lego*
curl -s https://api.github.com/repos/xenolf/lego/releases/latest | grep browser_download_url | grep linux_amd64 | cut -d '"' -f 4 | wget -i -
tar xf lego_vX.Y.Z_linux_amd64.tar.gz
sudo mv lego /usr/local/bin/lego
@avalero, what version of lego are you using? Could you please try the steps I mentioned above?
Hope it helps,