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 UDP. See RFC 1035, Sec. 4.2. (130.161.180.1, 130.161.180.65)
tudelft.nl zone: There was an error resolving the following NS name(s) to address(es): ns2.tudelft.nl
tudelft.nl/A: 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/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_)