Comment # 2 on bug 1119619 from Tomas Kuchta

This exact issue is also present in leap opensuse 15.0

Perhaps the package in opensuse should use default /etc/letsencrypt instead of
changing it to /etc/certbot at the certificate install only. Certbot is using
default /etc/letsencrypt for other sub-commands.

BTW: the link command for the workaround bellow need adjustment:
mv /etc/letsencrypt /etc/letsencrypt.empty
mv /etc/certbot /etc/letsencrypt
(cd /etc ; ln -s letsencrypt certbot)

After this all seems working fine.

Hope this helps,
Tomas