knotc zone-get returns nothing if the RR type is unknown
running knotd (Knot DNS), version 2.7.8
knotc> zone-begin sinodun.com.
OK
knotc> zone-get sinodun.com. www.sinodun.com. A
[sinodun.com.] www.sinodun.com. 3600 A 62.232.251.197
knotc> zone-get sinodun.com. www1.sinodun.com. A
error: (no such node in zone found) [sinodun.com.] www1.sinodun.com. A
knotc> zone-get sinodun.com. www1.sinodun.com. AA
knotc> zone-get sinodun.com. sinodun.com. CAA
knotc>
Strangely the CAA should work according to https://sslmate.com/caa/support