You have one and your configuration is buggy. Looks like you use a not working DNS.
Please use online tools.
:~$ dig DS i2rs.nl.
; <<>> DiG 9.11.3-1ubuntu1.11-Ubuntu <<>> DS i2rs.nl.
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 14255
;; flags: qr rd ra ad; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;i2rs.nl. IN DS;; ANSWER SECTION:
i2rs.nl. 3600 IN DS 57517 8 2 9B99CAF6CD9D1A76295CEA22AE84A80C71F034B207808899FEE1D248 09457145;; Query time: 21 msec
;; SERVER: 192.168.0.1#53(192.168.0.1)
;; WHEN: Tue Jan 19 10:20:25 CET 2021
;; MSG SIZE rcvd: 84