Welcome @nodiaque
I see a TXT record right now but it has no value. Did you create that? Normally the DNS plug-in creates a TXT record with the value required for the DNS Challenge. It is odd to see a TXT record with no value.
Can you show the certbot command you used? Please redact any duckdns-token
dig TXT _acme-challenge.servraid.duckdns.org @ns1.duckdns.org +short
""