Please fill out the fields below so we can help you better. Note: you must provide your domain name to get help. Domain names for issued certificates are all made public in Certificate Transparency logs (e.g. https://crt.sh/?q=example.com), so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help.
DNS validation would require a TXT record be created in the Internet zone for the FQDN as: _acme-challenge.webmin01.yriver-tech.com
The authoritative DNS server is at IP 3.16.89.140: nslookup -q=ns yriver-tech.com ns1.yriver-tech.com internet address = 3.16.89.140 ns2.yriver-tech.com internet address = 3.16.89.140
Unfortunately I’m not familiar with how to instruct Webmin to handle DNS authentication.