Hi @EdGeis,
The right way should be this:
Before doing any change, please, backup (as user root):
tar zcvf /root/backup_etc_letsencrypt_2018-Oct-06.tar.gz /etc/letsencrypt/
And then, recreate the symbolic links pointing to the last files inside archive/mydomain.com
cd /etc/letsencrypt/live/mydomain.com/
ln -sf ../../archive/mydomain.com/cert2.pem cert.pem
ln -sf ../../archive/mydomain.com/chain2.pem chain.pem
ln -sf ../../archive/mydomain.com/fullchain2.pem fullchain.pem
ln -sf ../../archive/mydomain.com/privkey2.pem privkey.pem
Good luck,
sahsanu