Yes all of that are correctly on config
DNS_CERT=1, and set up CERT_EMAIL, DNS_PLUGIN and DNS_ENV in your configuration file.
THIS IS THE CADDY.LOG
2020/06/05 08:41:03 [INFO] [nextocloud2.mybusiness.com] acme: Waiting for DNS record propagation.
2020/06/05 08:41:05 [INFO] [nextocloud2.mybusiness.com] acme: Cleaning DNS-01 challenge
2020/06/05 08:41:07 [INFO] Deactivating auth:
https://acme-staging-v02.api.letsencrypt.org/acme/authz-v3/62179603
2020/06/05 08:41:07 [ERROR][nextocloud2.mybusiness.com] failed to obtain certificate: acme: Error -> One or more domains had a problem:
[nextocloud2.mybusiness.com] time limit exceeded: last error: NS liberty.ns.cloudflare.com. returned NXDOMAIN for _acme-challenge.nextcloud2.mybusiness.com. (attempt 3/3; challenge=dns-01)
2020/06/05 08:41:08 failed to obtain certificate: acme: Error -> One or more domains had a problem:
[nextocloud2.mybusiness.com] time limit exceeded: last error: NS liberty.ns.cloudflare.com. returned NXDOMAIN for _acme-challenge.nextcloud2.mybusiness.com.
2020/06/05 08:40:55 [INFO] [nextocloud2.mybusiness.com] acme: Waiting for DNS record propagation.
2020/06/05 08:40:57 [INFO] [nextocloud2.mybusiness.com] acme: Waiting for DNS record propagation.
2020/06/05 08:41:00 [INFO] [nextocloud2.mybusiness.com] acme: Waiting for DNS record propagation.
2020/06/05 08:41:03 [INFO] [nextocloud2.mybusiness.com] acme: Waiting for DNS record propagation.
2020/06/05 08:41:05 [INFO] [nextocloud2.mybusiness.com] acme: Cleaning DNS-01 challenge
2020/06/05 08:41:07 [INFO] Deactivating auth:
https://acme-staging-v02.api.letsencrypt.org/acme/authz-v3/62179603
2020/06/05 08:41:07 [ERROR][nextocloud2.mybusiness.com] failed to obtain certificate: acme: Error -> One or more domains had a problem:
[nextocloud2.mybusiness.com] time limit exceeded: last error: NS liberty.ns.cloudflare.com. returned NXDOMAIN for _acme-challenge.nextcloud2.mybusiness.com. (attempt 3/3; challenge=dns-01)
2020/06/05 08:41:08 failed to obtain certificate: acme: Error -> One or more domains had a problem:
[nextcloud2.mybusiness.com] time limit exceeded: last error: NS liberty.ns.cloudflare.com. returned NXDOMAIN for _acme-challenge.nextcloud2.mybusiness.com.
2020/06/05 08:41:00 [INFO] [nextcloud2.mybusiness.com] acme: Waiting for DNS record propagation.
2020/06/05 08:41:03 [INFO] [nextcloud2.mybusiness.com] acme: Waiting for DNS record propagation.
2020/06/05 08:41:05 [INFO] [nextcloud2.mybusiness.com] acme: Cleaning DNS-01 challenge
2020/06/05 08:41:07 [INFO] Deactivating auth:
https://acme-staging-v02.api.letsencrypt.org/acme/authz-v3/62179603
2020/06/05 08:41:07 [ERROR][nextocloud2.mybusiness.com] failed to obtain certificate: acme: Error -> One or more domains had a problem:
[nextocloud2.mybusiness.com] time limit exceeded: last error: NS liberty.ns.cloudflare.com. returned NXDOMAIN for _acme-challenge.nextcloud2.mybusiness.com. (attempt 3/3; challenge=dns-01)
2020/06/05 08:41:08 failed to obtain certificate: acme: Error -> One or more domains had a problem:
[nextocloud2.mybusiness.com] time limit exceeded: last error: NS liberty.ns.cloudflare.com. returned NXDOMAIN for _acme-challenge.nextcloud2.mybusiness.com.
2020/06/05 08:40:55 [INFO] [nextocloud2.mybusiness.com] acme: Waiting for DNS record propagation.
2020/06/05 08:40:57 [INFO] [nextocloud2.mybusiness.com] acme: Waiting for DNS record propagation.
2020/06/05 08:41:00 [INFO] [nextocloud2.mybusiness.com] acme: Waiting for DNS record propagation.
2020/06/05 08:41:03 [INFO] [nextocloud2.mybusiness.com] acme: Waiting for DNS record propagation.
2020/06/05 08:41:05 [INFO] [nextocloud2.mybusiness.com] acme: Cleaning DNS-01 challenge
2020/06/05 08:41:07 [INFO] Deactivating auth:
https://acme-staging-v02.api.letsencrypt.org/acme/authz-v3/62179603
2020/06/05 08:41:07 [ERROR][nextocloud2.mybusiness.com] failed to obtain certificate: acme: Error -> One or more domains had a problem:
[nextocloud2.mybusiness.com] time limit exceeded: last error: NS liberty.ns.cloudflare.com. returned NXDOMAIN for _acme-challenge.nextcloud2.mybusiness. (attempt 3/3; challenge=dns-01)
2020/06/05 08:41:08 failed to obtain certificate: acme: Error -> One or more domains had a problem:
[nextocloud2.mybusiness.com] time limit exceeded: last error: NS liberty.ns.cloudflare.com. returned NXDOMAIN for _acme-challenge.nextcloud2.mybusiness.com.
Obviously i change my domain.com by mybusiness.com but i can send you to private if you want. or i can tell you my ssh connection if you can help me more i spend all the week on that and nothing.