My files in /etc/letsencrypt/live/* weren't symbolic link as they should be. Here's a patch.

letsencrypt_symbolic_link.sh

#!/bin/bash

for i in /etc/letsencrypt/live/* ; do
  if [ -d "$i" ]; then
    j=$(basename "$i")
    mv $i/fullchain.pem $i/fullchain.pem.old
    mv $i/cert.pem $i/cert.pem.old
    mv $i/chain.pem $i/chain.pem.old
    mv $i/privkey.pem $i/privkey.pem.old
    ln -s /etc/letsencrypt/archive/$j/fullchain1.pem /etc/letsencrypt/live/$j/fullchain.pem
    ln -s /etc/letsencrypt/archive/$j/cert1.pem /etc/letsencrypt/live/$j/cert.pem
    ln -s /etc/letsencrypt/archive/$j/chain1.pem /etc/letsencrypt/live/$j/chain.pem
    ln -s /etc/letsencrypt/archive/$j/privkey1.pem /etc/letsencrypt/live/$j/privkey.pem
  fi
done

Thanks to certbot/certbot#2550 (comment)