Can't access Home Assistant over ipv6

[lilithpro]

iOS device model, version and app version

Model Name: iPhone 15 / iPad Mini 6
Software Version: iOS 26.4.2 / iPadOS 26.4.2
App version: 2026.4.1 (2026.1904) & 2026.5.0 (2026.1949) TestFlight

Home Assistant Core Version

2026.3.1 Docker & 2026.4.4 Docker

Describe the bug
Can't connect the Companion App to the Home Assistant server using its ipv6 address, while access over Safari works fine

To Reproduce
Enter the ipv6 address (http://[fd00::abcd]:8123) as server URL in the Companion App.

Expected behavior
Connects successfully

Screenshots

Additional context
Connection over ipv4 works without issues, there are no errors in the home assistant logs, but there are lots (14) of webhook 404 errors when viewing the app protocols:
{
"date": 799340315.406546,
"id": "2A9720E8-5839-4ECA-87F4-FD069F270CD9",
"jsonPayload": {},
"text": "Webhook failed, server Zuhause, with status code 404 - URL: [fd00::abcd]",
"type": "networkRequest"
}

When setting up the app, the user selection and even creating the mobile app device in home assistant works
fine, only the frontend shows "loading" for a while and then fails.
Tested on multiple devices, with multiple app versions (latest and test flight) and multiple HA core versions
Please let me know if there is more i can test.

Greetings

[myokeeh]

It was working for me reliably then it recently stopped working. Still figuring out what's wrong.

NSURLErrorDomain

Code -1001

[FrancoisDoussin]

Same here, it was working for ages, but now it doesn't.

The strangest thing is that it works when I use the app as a widget but it's impossible to open application.

[lilithpro]

Good to know that it may not be an error with my setup. I guess the problem might have been introduced in a recent app update.

[bgoncal]

I'll be checking it this week. Meanwhile if anyone is in TestFlight can you rollback to an older version of the app just to validate?

[myokeeh]

It works on version 2026.1862 and stops working on 2026.1865 and beyond.