curl -v -6 https://apt.syncthing.net
* Trying [2603:1020:200::682f:a65b]:443...
* Connected to apt.syncthing.net (2603:1020:200::682f:a65b) port 443 (#0)
* ALPN: offers h2,http/1.1
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* CAfile: /etc/ssl/certs/ca-certificates.crt
* CApath: /etc/ssl/certs
but ping works fine
ping -6 apt.syncthing.net
PING apt.syncthing.net(2603:1020:200::682f:a65b (2603:1020:200::682f:a65b)) 56 data bytes
64 bytes from 2603:1020:200::682f:a65b (2603:1020:200::682f:a65b): icmp_seq=1 ttl=106 time=166 ms
64 bytes from 2603:1020:200::682f:a65b (2603:1020:200::682f:a65b): icmp_seq=2 ttl=106 time=167 ms
64 bytes from 2603:1020:200::682f:a65b (2603:1020:200::682f:a65b): icmp_seq=3 ttl=106 time=166 ms
64 bytes from 2603:1020:200::682f:a65b (2603:1020:200::682f:a65b): icmp_seq=4 ttl=106 time=166 ms