EDIT: Figured it out. I had a blacklist enabled (ThreatView.io) which apparently has Canonical IP addresses in it. Lost a day but at least everything (seems) is working again!


I have the strangest problem. For the most part, I have zero issues with networking. However, lately I can't refresh my snap apps and can't reach some github repos. Otherwise, networking is just fine. Some things I've done:
  • Rebooted
  • Shutdown the pi-hole server and use firewall's DNS
  • Disconnected mobile phone from home internet to use mobile internet (SUCCESS: was able to reach https://api.snapcraft.io via Firefox mobile)
  • Turn on VPN (SUCCESS: was able to reach https://api.snapcraft.io via Firefox desktop and refresh my snaps)​
Some CLI output:
Code:
curl --verbose https://api.snapcraft.io
* Host api.snapcraft.io:443 was resolved.
* IPv6: 2620:2d:4000:1010::117, 2620:2d:4000:1010::2e6, 2620:2d:4000:1010::42, 2620:2d:4000:1010::2d6
* IPv4: 185.125.188.58, 185.125.188.57, 185.125.188.59, 185.125.188.54
*   Trying 185.125.188.58:443...
*   Trying [2620:2d:4000:1010::117]:443...
* Immediate connect fail for 2620:2d:4000:1010::117: Cannot assign requested address
*   Trying [2620:2d:4000:1010::2e6]:443...
* Immediate connect fail for 2620:2d:4000:1010::2e6: Cannot assign requested address
*   Trying [2620:2d:4000:1010::42]:443...
* Immediate connect fail for 2620:2d:4000:1010::42: Cannot assign requested address
*   Trying [2620:2d:4000:1010::2d6]:443...
* Immediate connect fail for 2620:2d:4000:1010::2d6: Cannot assign requested address
Code:
sudo snap refresh snapd
error: unable to contact snap store
Code:
traceroute api.snapcraft.io
traceroute to api.snapcraft.io (185.125.188.57), 30 hops max, 60 byte packets
1 * * *
2 * * *
3 * * *
4 * * *
5 * * *
...
30 * * *​
​
Code:
ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
2: enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 08:62:66:2c:51:02 brd ff:ff:ff:ff:ff:ff
inet 10.50.0.52/24 brd 10.50.0.255 scope global dynamic noprefixroute enp2s0
valid_lft 10953sec preferred_lft 10953sec​​​
Since I can reach snapcraft via mobile data and VPN, I know the issue is either my network or ISP. I'm at my wits end trying to figure out what the issue is. Anyone have any insight?

Thanks in advance.