sometimes resolving failed

[icebluey]

Sometimes resolving failed, such as:

$ wget https://zlib.net/zlib-1.2.11.tar.gz
--2021-10-01 10:30:20--  https://zlib.net/zlib-1.2.11.tar.gz
Resolving zlib.net (zlib.net)... failed: Name or service not known.
wget: unable to resolve host address ‘zlib.net’

But I run this command second time, it can resolve domain name successfully.
Not just wget command, docker faild to pull images because of this issue sometimes too.

dnscrypt-proxy is running as service and listening on '127.0.0.1:53' :

$ systemctl status dnscrypt-proxy.service 
● dnscrypt-proxy.service - DNSCrypt-proxy client
   Loaded: loaded (/usr/lib/systemd/system/dnscrypt-proxy.service; enabled; vendor preset: disabled)
   Active: active (running)
 Main PID: 17877 (dnscrypt-proxy)
   CGroup: /system.slice/dnscrypt-proxy.service
           └─17877 /usr/bin/dnscrypt-proxy -config /etc/dnscrypt-proxy/dnscrypt-proxy.toml

dnscrypt-proxy[17877]: [2021-10-01 10:41:35] [NOTICE] Source [public-resolvers] loaded
dnscrypt-proxy[17877]: [2021-10-01 10:41:36] [NOTICE] Source [relays] loaded
dnscrypt-proxy[17877]: [2021-10-01 10:41:36] [NOTICE] Firefox workaround initialized
dnscrypt-proxy[17877]: [2021-10-01 10:41:36] [NOTICE] [google] OK (DoH) - rtt: 8ms
dnscrypt-proxy[17877]: [2021-10-01 10:41:36] [NOTICE] [cloudflare] OK (DoH) - rtt: 32ms
dnscrypt-proxy[17877]: [2021-10-01 10:41:36] [NOTICE] Sorted latencies:
dnscrypt-proxy[17877]: [2021-10-01 10:41:36] [NOTICE] -     8ms google
dnscrypt-proxy[17877]: [2021-10-01 10:41:36] [NOTICE] -    32ms cloudflare
dnscrypt-proxy[17877]: [2021-10-01 10:41:36] [NOTICE] Server with the lowest initial latency: google (rtt: 8ms)
dnscrypt-proxy[17877]: [2021-10-01 10:41:36] [NOTICE] dnscrypt-proxy is ready - live servers: 2

$ dnscrypt-proxy -version
2.1.1

I am not sure this is dnscrypt-proxy's issue, but this issue does happen.
And I can not reproduce this issue on my purpose.

[ghost]

Turn on the query log (not the application log), then either try to reproduce or just wait for it to happen and remember the time so you can look it up. Then post the lines where it fails here.