Some DNS records were found that indicate TXT records may have been incorrectly manually entered into DNS editor interfaces. The correct way to enter these records is to either remove the domain from the label (so enter "_acme-challenge.www.example.org" as "_acme-challenge.www") or include a period (.) at the end of the label (enter "_acme-challenge.example.org.").
The following probably-erroneous TXT records were found:
_acme-challenge.biggszm.duckdns.org.biggszm.duckdns.org. 0 IN TXT ""
_acme-challenge.biggszm.duckdns.org.biggszm.duckdns.org. 0 IN TXT ""
Challenge update failures for biggszm.duckdns.org in order https://acme-staging-v02.api.letsencrypt.org/acme/order/5751349/101906200
acme: error code 403 "urn:ietf:params:acme:error:unauthorized": Incorrect TXT record "" found at _acme-challenge.biggszm.duckdns.org