Thanks all, I've found the problem it was my ISP router that was blocking it. --> solved.

Thanks @InnerScientist@lemmy.world & @ark3@lemmy.dbzer0.com

Actually I don't think it's the firewall, because all the other programs, protocol are working fine. I've tried with chrony too but I get

No suitable source for synchronisation

May be because the client is a VM ?

I would momentarily drop all rules (if possible) to see if it has to do with firewall at all

Update your nftables rulefile or use nft commands to update your firewall to the following:

# extract
chain OUT {
    type filter hook output priority 0; policy drop;
    udp dport 123 accept

    limit rate 3/second log prefix "Nftables Blocked: OUT: "
}

chain IN {
    type filter hook input priority 0; policy drop;
    ct state established, related accept

    limit rate 3/second log prefix "Nftables Blocked: IN: "
}

Blocked pakets will show up in the kernel log (dmesg/journalcl)

If you want more information on why it is blocked then enable nftrace for those packets

nft add rule inet/ip/ip6 tablename OUT udp dport 123 meta nftrace set 1
nft add rule inet/ip/ip6 tablename IN udp dport 123 meta nftrace set 1
nft monitor trace

Or

nft add rule inet/ip/ip6 tablename OUT meta nftrace set 1

Or maybe even

nft add rule inet/ip/ip6 tablename PREROUTING udp dport 123 meta nftrace set 1

Additionally you can use tcpdump -i to show network packets before they enter the firewall, there you should be able to tell what it's a trying to do.