Cannot "Activate" my HA server, logs contain "Failed to fetch device registry on server Home"

**iOS device model, version and app version**

Model Name: iPhone 16
Software Version: 26.5
App version: 2026.7.0 (2026.2208)

**Home Assistant Core Version**
2026.7.2

**Describe the bug**
About two weeks ago I noticed the companion app was defaulting to my second server named "shop", this is unusual as it always defaults to my "Home" server. I accessed `Settings > Companion App` and selected the Home server, then clicked the `Activate` button. Nothing happens. No error or anything.

**To Reproduce**
1. Start the iOS app
2. click `Settings > Companion App`
3. Selected the Home server (server that isn't currently active)
4. Click the `Activate` button

**Expected behavior**
The app would change to my requested server and show the Overview dashboard.
Note: I've been using the app for a couple years in this way.

**Screenshots**
I made a [quick screen recording](https://youtube.com/shorts/PLTWIizhKh4) that shows the issues

**Additional context**
1. I've not made any network changes
2. I can access the HA server in my browser on my phone - this is only a companion app issue
3. I checked the logs and there is an entry "Failed to fetch device registry on server Home" with this in the details:

```
{
"error" : "The operation couldn’t be completed. (HAKit.HADataError error 1.)"
}
```

4. I found [Issue 29772](https://github.com/home-assistant/frontend/issues/29772) which sounded pretty similar, but that seems to have been fixed a while ago and I'm still experiencing the issue.

Start by reproducing the failure through Settings > Companion App with the Home server selected, then inspect the log entry “Failed to fetch device registry on server Home” and its HAKit.HADataError details. Compare the failed Activate behavior with the expected server switch and Overview dashboard loading; done means the selected server activates successfully.

Written by the indexing model from the issue text.