Manjaro time servers not reachable on port 123

Support Network
1

I notice the following error messages in systemd-journal regularly.

Mar 13 17:23:06 lw1380 systemd-timesyncd[485]: Timed out waiting for reply from 3.121.254.221:123 (3.manjaro.pool.ntp.org).
Mar 13 17:22:56 lw1380 systemd-timesyncd[485]: Timed out waiting for reply from 116.202.222.249:123 (3.manjaro.pool.ntp.org).
Mar 13 17:22:45 lw1380 systemd-timesyncd[485]: Timed out waiting for reply from 78.47.193.211:123 (3.manjaro.pool.ntp.org).
Mar 13 17:22:35 lw1380 systemd-timesyncd[485]: Timed out waiting for reply from 129.70.132.36:123 (3.manjaro.pool.ntp.org).
Mar 13 17:22:25 lw1380 systemd-timesyncd[485]: Timed out waiting for reply from 136.243.177.133:123 (2.manjaro.pool.ntp.org).
Mar 13 17:22:15 lw1380 systemd-timesyncd[485]: Timed out waiting for reply from 162.159.200.1:123 (2.manjaro.pool.ntp.org).
Mar 13 17:22:04 lw1380 systemd-timesyncd[485]: Timed out waiting for reply from 131.188.3.223:123 (2.manjaro.pool.ntp.org).
Mar 13 17:21:54 lw1380 systemd-timesyncd[485]: Timed out waiting for reply from 85.90.244.165:123 (2.manjaro.pool.ntp.org).

The NTP server are reachable but not responding on port 123:

$ sudo nmap -sU -p 123 --reason 3.manjaro.pool.ntp.org
Starting Nmap 7.91 ( https://nmap.org ) at 2021-03-13 17:58 CET
Nmap scan report for 3.manjaro.pool.ntp.org (176.221.42.125)
Host is up, received syn-ack ttl 56 (0.028s latency).
Other addresses for 3.manjaro.pool.ntp.org (not scanned): 157.90.24.29 62.141.37.84 131.188.3.223
rDNS record for 176.221.42.125: janetzki.eu

PORT    STATE  SERVICE REASON
123/udp closed ntp     port-unreach ttl 64

Nmap done: 1 IP address (1 host up) scanned in 0.48 seconds
$

I did not change the timedate configuration since installation.

$ timedatectl show-timesync
FallbackNTPServers=0.manjaro.pool.ntp.org 1.manjaro.pool.ntp.org 2.manjaro.pool.ntp.org 3.manjaro.pool.ntp.org
ServerName=3.manjaro.pool.ntp.org
ServerAddress=131.188.3.223
RootDistanceMaxUSec=5s
PollIntervalMinUSec=32s
PollIntervalMaxUSec=34min 8s
PollIntervalUSec=34min 8s
Frequency=0
$
2

From my part of the world,

sudo nmap -sU -p 123 176.221.42.125        
Starting Nmap 7.91 ( https://nmap.org ) at 2021-03-13 19:52 CET
Nmap scan report for janetzki.eu (176.221.42.125)
Host is up (0.042s latency).

PORT    STATE SERVICE
123/udp open  ntp

Nmap done: 1 IP address (1 host up) scanned in 1.15 seconds

Sometimes, Home Router/ISP forbid using alternative Time server form the Internet. Does any other Timeserver work in your Network?