nl to tudelft.nl: No valid RRSIGs made by a key corresponding to a DS RR were found covering the DNSKEY RRset, resulting in no secure entry point (SEP) into the zone. See RFC 4035, Sec. 2.2, RFC 6840, Sec. 5.11.
tudelft.nl zone: The server(s) were not responsive to queries over TCP. See RFC 1035, Sec. 4.2. (130.161.180.1, 130.161.180.65)
tudelft.nl/AAAA: No response was received from the server over UDP (tried 12 times). See RFC 1035, Sec. 4.2. (130.161.180.1, 130.161.180.65, UDP_-_NOEDNS_)
tudelft.nl/DNSKEY: No response was received from the server over UDP (tried 12 times). See RFC 1035, Sec. 4.2. (130.161.180.1, 130.161.180.65, UDP_-_NOEDNS_)
tudelft.nl/DNSKEY: No response was received from the server over UDP (tried 4 times). See RFC 1035, Sec. 4.2. (130.161.180.1, 130.161.180.65, UDP_-_EDNS0_512_D_KN)
tudelft.nl/MX: No response was received from the server over UDP (tried 12 times). See RFC 1035, Sec. 4.2. (130.161.180.65, UDP_-_NOEDNS_)
tudelft.nl/MX: No response was received from the server over UDP (tried 4 times). See RFC 1035, Sec. 4.2. (130.161.180.1, 130.161.180.65, UDP_-_EDNS0_512_D_KN)
tudelft.nl/NS: No response was received from the server over UDP (tried 12 times). See RFC 1035, Sec. 4.2. (130.161.180.1, 130.161.180.65, UDP_-_NOEDNS_)
tudelft.nl/NSEC3PARAM: No response was received from the server over UDP (tried 12 times). See RFC 1035, Sec. 4.2. (130.161.180.65, UDP_-_NOEDNS_)
tudelft.nl/SOA: No response was received from the server over TCP (tried 3 times). See RFC 1035, Sec. 4.2. (130.161.180.1, 130.161.180.65, TCP_-_EDNS0_4096_D_N)
tudelft.nl/SOA: No response was received from the server over UDP (tried 12 times). See RFC 1035, Sec. 4.2. (130.161.180.1, 130.161.180.65, UDP_-_NOEDNS_, UDP_-_NOEDNS__0x20)
tudelft.nl/TXT: No response was received from the server over UDP (tried 12 times). See RFC 1035, Sec. 4.2. (130.161.180.1, 130.161.180.65, UDP_-_NOEDNS_)
tudelft.nl/DNSKEY has errors; select the "Denial of existence" DNSSEC option to see them.
tudelft.nl/CNAME has errors; select the "Denial of existence" DNSSEC option to see them.
dkzob.vkh98.tudelft.nl/A has errors; select the "Denial of existence" DNSSEC option to see them.