DNS queries are fine, but a failure log appears.

### Prerequisites

- [X] I have checked the [Wiki](https://github.com/AdguardTeam/AdGuardHome/wiki) and [Discussions](https://github.com/AdguardTeam/AdGuardHome/discussions/categories/q-a) and found no answer

- [X] I have searched other issues and found no duplicates

- [X] I want to report a bug and not [ask a question or ask for help](https://github.com/AdguardTeam/AdGuardHome/discussions/categories/q-a)

- [X] I have set up AdGuard Home correctly and [configured clients to use it](https://github.com/AdguardTeam/AdGuardHome/wiki/Clients). (Use the [Discussions](https://github.com/AdguardTeam/AdGuardHome/discussions/categories/q-a) for help with installing and configuring clients.)

### Platform (OS and CPU architecture)

Linux, AMD64 (aka x86_64)

### Installation

Docker

### Setup

On a router, DHCP is handled by the router

### AdGuard Home version

v0.107.44

### Action

docker logs -f adg

### Expected result

```
Attaching to adg
adg | 2024/02/07 11:08:26.656715 [info] AdGuard Home, version v0.107.44
adg | 2024/02/07 11:08:26.658716 [info] tls: using default ciphers
adg | 2024/02/07 11:08:26.659697 [info] safesearch default: disabled
adg | 2024/02/07 11:08:26.670313 [info] Initializing auth module: /opt/adguardhome/work/data/sessions.db
adg | 2024/02/07 11:08:26.670811 [info] auth: initialized. users:1 sessions:6
adg | 2024/02/07 11:08:26.670982 [info] tls: number of certs: 2
adg | 2024/02/07 11:08:26.671055 [info] tls: got an intermediate cert
adg | 2024/02/07 11:08:26.692360 [info] AdGuard Home updates are disabled
adg | 2024/02/07 11:08:26.692371 [info] web: initializing
adg | 2024/02/07 11:08:26.762724 [info] dnsproxy: cache: enabled, size 4096 b
adg | 2024/02/07 11:08:26.762737 [info] dnsproxy: max goroutines is set to 300
adg | 2024/02/07 11:08:26.763395 [info] dnsproxy: cache: disabled
adg | 2024/02/07 11:08:26.763733 [info] clients: processing addresses
adg | 2024/02/07 11:08:26.764023 [info] AdGuard Home is available at the following addresses:
adg | 2024/02/07 11:08:26.764087 [info] go to https://---.---.app:443
adg | 2024/02/07 11:08:26.764180 [info] go to http://127.0.0.1:80
adg | 2024/02/07 11:08:26.764183 [info] go to http://172.26.0.2:80
adg | 2024/02/07 11:08:28.648623 [info] dnsproxy: starting dns proxy server
adg | 2024/02/07 11:08:28.648643 [info] Cache TTL override is enabled. Min=210, Max=4294967295
adg | 2024/02/07 11:08:28.648645 [info] The server is configured to refuse ANY requests
adg | 2024/02/07 11:08:28.648647 [info] dnsproxy: cache: enabled, size 4194304 b
adg | 2024/02/07 11:08:28.648653 [info] dnsproxy: max goroutines is set to 300
adg | 2024/02/07 11:08:28.648660 [info] dnsproxy: creating udp server socket 0.0.0.0:53
adg | 2024/02/07 11:08:28.648730 [info] dnsproxy: listening to udp://[::]:53
adg | 2024/02/07 11:08:28.648738 [info] dnsproxy: creating tcp server socket 0.0.0.0:53
adg | 2024/02/07 11:08:28.648764 [info] dnsproxy: listening to tcp://[::]:53
adg | 2024/02/07 11:08:28.648768 [info] dnsproxy: creating tls server socket 0.0.0.0:853
adg | 2024/02/07 11:08:28.648801 [info] dnsproxy: listening to tls://[::]:853
adg | 2024/02/07 11:08:28.648806 [info] Creating a QUIC listener
adg | 2024/02/07 11:08:28.648976 [info] Listening to quic://[::]:853
adg | 2024/02/07 11:08:28.649088 [info] dnsproxy: entering udp listener loop on [::]:53
adg | 2024/02/07 11:08:28.649158 [info] Entering the DNS-over-QUIC listener loop on [::]:853
adg | 2024/02/07 11:08:28.649298 [info] dnsproxy: entering tcp listener loop on [::]:53
adg | 2024/02/07 11:08:28.649327 [info] dnsproxy: entering tls listener loop on [::]:853
```

### Actual result

```
Attaching to adg
adg | 2024/02/07 11:08:26.656715 [info] AdGuard Home, version v0.107.44
adg | 2024/02/07 11:08:26.658716 [info] tls: using default ciphers
adg | 2024/02/07 11:08:26.659697 [info] safesearch default: disabled
adg | 2024/02/07 11:08:26.670313 [info] Initializing auth module: /opt/adguardhome/work/data/sessions.db
adg | 2024/02/07 11:08:26.670811 [info] auth: initialized. users:1 sessions:6
adg | 2024/02/07 11:08:26.670982 [info] tls: number of certs: 2
adg | 2024/02/07 11:08:26.671055 [info] tls: got an intermediate cert
adg | 2024/02/07 11:08:26.692360 [info] AdGuard Home updates are disabled
adg | 2024/02/07 11:08:26.692371 [info] web: initializing
adg | 2024/02/07 11:08:26.762724 [info] dnsproxy: cache: enabled, size 4096 b
adg | 2024/02/07 11:08:26.762737 [info] dnsproxy: max goroutines is set to 300
adg | 2024/02/07 11:08:26.763395 [info] dnsproxy: cache: disabled
adg | 2024/02/07 11:08:26.763733 [info] clients: processing addresses
adg | 2024/02/07 11:08:26.764023 [info] AdGuard Home is available at the following addresses:
adg | 2024/02/07 11:08:26.764087 [info] go to https://---.---.app:443
adg | 2024/02/07 11:08:26.764180 [info] go to http://127.0.0.1:80
adg | 2024/02/07 11:08:26.764183 [info] go to http://172.26.0.2:80
adg | 2024/02/07 11:08:28.648623 [info] dnsproxy: starting dns proxy server
adg | 2024/02/07 11:08:28.648643 [info] Cache TTL override is enabled. Min=210, Max=4294967295
adg | 2024/02/07 11:08:28.648645 [info] The server is configured to refuse ANY requests
adg | 2024/02/07 11:08:28.648647 [info] dnsproxy: cache: enabled, size 4194304 b
adg | 2024/02/07 11:08:28.648653 [info] dnsproxy: max goroutines is set to 300
adg | 2024/02/07 11:08:28.648660 [info] dnsproxy: creating udp server socket 0.0.0.0:53
adg | 2024/02/07 11:08:28.648730 [info] dnsproxy: listening to udp://[::]:53
adg | 2024/02/07 11:08:28.648738 [info] dnsproxy: creating tcp server socket 0.0.0.0:53
adg | 2024/02/07 11:08:28.648764 [info] dnsproxy: listening to tcp://[::]:53
adg | 2024/02/07 11:08:28.648768 [info] dnsproxy: creating tls server socket 0.0.0.0:853
adg | 2024/02/07 11:08:28.648801 [info] dnsproxy: listening to tls://[::]:853
adg | 2024/02/07 11:08:28.648806 [info] Creating a QUIC listener
adg | 2024/02/07 11:08:28.648976 [info] Listening to quic://[::]:853
adg | 2024/02/07 11:08:28.649088 [info] dnsproxy: entering udp listener loop on [::]:53
adg | 2024/02/07 11:08:28.649158 [info] Entering the DNS-over-QUIC listener loop on [::]:853
adg | 2024/02/07 11:08:28.649298 [info] dnsproxy: entering tcp listener loop on [::]:53
adg | 2024/02/07 11:08:28.649327 [info] dnsproxy: entering tls listener loop on [::]:853
adg | 2024/02/07 11:08:49.074292 [error] dnsproxy: 8.20.247.20:53: response received over udp: "exchanging with 8.20.247.20:53 over udp: read udp 172.26.0.2:52726->8.20.247.20:53: i/o timeout"
adg | 2024/02/07 11:08:49.074306 [error] dnsproxy: 168.126.63.2:53: response received over udp: "exchanging with 168.126.63.2:53 over udp: read udp 172.26.0.2:52248->168.126.63.2:53: i/o timeout"
adg | 2024/02/07 11:08:49.074327 [error] dnsproxy: 168.126.63.2:53: response received over udp: "exchanging with 168.126.63.2:53 over udp: read udp 172.26.0.2:54699->168.126.63.2:53: i/o timeout"
adg | 2024/02/07 11:08:49.074332 [error] dnsproxy: 8.20.247.20:53: response received over udp: "exchanging with 8.20.247.20:53 over udp: read udp 172.26.0.2:42247->8.20.247.20:53: i/o timeout"
adg | 2024/02/07 11:08:49.074335 [error] dnsproxy: 208.67.220.220:53: response received over udp: "exchanging with 208.67.220.220:53 over udp: read udp 172.26.0.2:45407->208.67.220.220:53: i/o timeout"
adg | 2024/02/07 11:08:49.074347 [error] dnsproxy: 168.126.63.1:53: response received over udp: "exchanging with 168.126.63.1:53 over udp: read udp 172.26.0.2:43850->168.126.63.1:53: i/o timeout"
adg | 2024/02/07 11:08:49.074350 [error] dnsproxy: 8.8.4.4:53: response received over udp: "exchanging with 8.8.4.4:53 over udp: read udp 172.26.0.2:38987->8.8.4.4:53: i/o timeout"
adg | 2024/02/07 11:08:49.074355 [error] dnsproxy: 156.154.71.2:53: response received over udp: "exchanging with 156.154.71.2:53 over udp: read udp 172.26.0.2:48121->156.154.71.2:53: i/o timeout"
adg | 2024/02/07 11:08:49.074363 [error] dnsproxy: 203.248.252.2:53: response received over udp: "exchanging with 203.248.252.2:53 over udp: read udp 172.26.0.2:45793->203.248.252.2:53: i/o timeout"
adg | 2024/02/07 11:08:49.074365 [error] dnsproxy: 1.0.0.1:53: response received over udp: "exchanging with 1.0.0.1:53 over udp: read udp 172.26.0.2:34784->1.0.0.1:53: i/o timeout"
adg | 2024/02/07 11:08:49.074370 [error] dnsproxy: 208.67.220.220:53: response received over udp: "exchanging with 208.67.220.220:53 over udp: read udp 172.26.0.2:60015->208.67.220.220:53: i/o timeout"
adg | 2024/02/07 11:08:49.074381 [error] dnsproxy: 8.8.4.4:53: response received over udp: "exchanging with 8.8.4.4:53 over udp: read udp 172.26.0.2:56328->8.8.4.4:53: i/o timeout"
adg | 2024/02/07 11:08:49.074381 [error] dnsproxy: 208.67.220.220:53: response received over udp: "exchanging with 208.67.220.220:53 over udp: read udp 172.26.0.2:34987->208.67.220.220:53: i/o timeout"
adg | 2024/02/07 11:08:49.074386 [error] dnsproxy: 149.112.112.112:53: response received over udp: "exchanging with 149.112.112.112:53 over udp: read udp 172.26.0.2:33072->149.112.112.112:53: i/o timeout"
adg | 2024/02/07 11:08:49.074393 [error] dnsproxy: 1.0.0.1:53: response received over udp: "exchanging with 1.0.0.1:53 over udp: read udp 172.26.0.2:55983->1.0.0.1:53: i/o timeout"
adg | 2024/02/07 11:08:49.074398 [error] dnsproxy: 168.126.63.2:53: response received over udp: "exchanging with 168.126.63.2:53 over udp: read udp 172.26.0.2:49823->168.126.63.2:53: i/o timeout"
adg | 2024/02/07 11:08:49.074402 [error] dnsproxy: 8.8.4.4:53: response received over udp: "exchanging with 8.8.4.4:53 over udp: read udp 172.26.0.2:42199->8.8.4.4:53: i/o timeout"
adg | 2024/02/07 11:08:49.074310 [error] dnsproxy: 8.8.4.4:53: response received over udp: "exchanging with 8.8.4.4:53 over udp: read udp 172.26.0.2:45792->8.8.4.4:53: i/o timeout"
adg | 2024/02/07 11:08:49.074408 [error] dnsproxy: 156.154.71.2:53: response received over udp: "exchanging with 156.154.71.2:53 over udp: read udp 172.26.0.2:47391->156.154.71.2:53: i/o timeout"
```

### Additional information and/or screenshots

## dns query from docker exec
of course, adg container can query dns from 8.8.4.4 172.26.0.2 1.0.0.1, etc.

adg is the adguard home docker container
```
cola@docker-adguard:/_DATA/appdata/docker-compose/adg> docker exec adg nslookup naver.com 8.8.4.4
Server: 8.8.4.4
Address: 8.8.4.4:53

Non-authoritative answer:
Name: naver.com
Address: 223.130.200.107
Name: naver.com
Address: 223.130.200.104
Name: naver.com
Address: 223.130.195.200
Name: naver.com
Address: 223.130.195.95

Non-authoritative answer:
```

## A log of successful queries is left.
of course, adg query dns from 168.126.63.2 successfully.

## failed on test upstream

However, the docker logs are showing i/o time out errors.
It appears that you are checking the connection status in a different way than the actual DNS query.
What method are you using?