IPv6 not working, but can't disable it either

My initial problem is that I am no longer able to download updates for my HACS integrations. I see the following error in the logs:

A timeout of 60! seconds was encountered while downloading https://raw.githubusercontent.com/<some_integration>..., using over 60 seconds to download a single file is not normal. This is not a problem with HACS but how your host communicates with GitHub. Retrying up to 5 times to mask/hide your host/network problems to stop the flow of issues opened about it. Tries left 1

When looking up this error message, it is said that this is likely caused by trying to download via IPv6, while IPv6 is not working. If I ping a public IPv6 address this is indeed not working on my setup, while for IPv4 this is working.

It was suggested to disable IPv6 in Settings > System > Network > WLAN0 > IPv6, but when I do that, I get a pop-up with the following message:

Failed to change network settings
Activating connection failed, check connection settings.

So I’m stuck in a state where I can’t update my integrations…

I would either need help with (1) disabling IPv6 OR (2) get IPv6 to work.

My ISP is Telenet. I’ve also tried to ping an IPv6 address from my Windows laptop and this also doesn’t work. Even when I (briefly) disabled the IPv6 firewall in the settings from my ISP.

I’m running HA on a RPi 3B+, connected on wlan0. I have NGINX reverse proxy setup and my instance is availble via duckdns, but all via IPv4…

Thank you

My network configuration was done using a config file on a USB stick. Setting method=disabled in the [ipv6] tag disabled IPv6, allowing me to update my integrations again…