[knot-dns-users] Warning about NOTAUTH error from notify

Hi all, I can't quite figure this out, I have two servers running Knot DNS 3.0.3 on Ubuntu 20.04. horus.bastetrix.net is the primary, sekhmet.bastetrix.net is the secondary. One of the zones hosted on these servers is selfhosting.cloud. Whenever I commit a change to selfhosting.cloud, this happens in the log. As you can see, for some reason the IPv4 address returns a NOTAUTH error and then Knot successfully notifies over IPv6. Dec 27 00:53:37 horus.bastetrix.net knotd[174159]: warning: [selfhosting.cloud.] notify, outgoing, remote 192.195.251.53@53, server responded with error 'NOTAUTH' Dec 27 00:53:37 horus.bastetrix.net knotd[174159]: info: [selfhosting.cloud.] notify, outgoing, remote 2620:98:400c::53@53, serial 5 Dec 27 00:53:38 horus.bastetrix.net knotd[174159]: info: [selfhosting.cloud.] IXFR, outgoing, remote 2620:98:400c::53@36778, started, serial 4 -> 5 Dec 27 00:53:38 horus.bastetrix.net knotd[174159]: info: [selfhosting.cloud.] IXFR, outgoing, remote 2620:98:400c::53@36778, finished, 0.00 seconds, 1 messages, 295 bytes sekhmet only logs a successful notify and IXFR from the v6 address, nothing about the failed v4 notify: Dec 27 00:53:37 sekhmet.bastetrix.net knotd[536887]: info: [selfhosting.cloud.] notify, incoming, remote 2620:98:400a::53@58782, serial 5 Dec 27 00:53:38 sekhmet.bastetrix.net knotd[536887]: info: [selfhosting.cloud.] refresh, remote 2620:98:400a::53@53, remote serial 5, zone is outdated Dec 27 00:53:38 sekhmet.bastetrix.net knotd[536887]: info: [selfhosting.cloud.] IXFR, incoming, remote 2620:98:400a::53@53, started Dec 27 00:53:38 sekhmet.bastetrix.net knotd[536887]: info: [selfhosting.cloud.] IXFR, incoming, remote 2620:98:400a::53@53, finished, 0.00 seconds, 1 messages, 295 bytes Dec 27 00:53:38 sekhmet.bastetrix.net knotd[536887]: info: [selfhosting.cloud.] refresh, remote 2620:98:400a::53@53, zone updated, 0.40 seconds, serial 4 -> 5 Dec 27 00:53:38 sekhmet.bastetrix.net knotd[536887]: info: [selfhosting.cloud.] zone file updated, serial 4 -> 5 I am attaching the knot.conf for both servers. I double checked both configs multiple times and don't see why that particular warning is happening during zone notify. Can someone shed some light on this mystery? -- Sadiq Saif https://bastetrix.com