Connection instability when switching between LAN, VPN, and Nabu Casa remote access

I wanted to report an issue I encountered with the Home Assistant iOS app related to connection handling when using a single server configuration with both local and Nabu Casa access.

**Environment:**

- Home Assistant OS
- Core: 2026.4.4
- Supervisor: 2026.04.2
- Frontend: 20260325.8
- iOS Companion App: 2026.4.1 (2026.1904)
- iOS: 26.4.2

**Issue:**
When using a single server entry (with both internal and external URLs), the app had difficulty switching between local (LAN/VPN) and remote (Nabu Casa) connections. I experienced:

- App getting stuck on “Connecting” or losing connection
- WebSocket failing to establish or reconnect reliably
- Login/auth webview occasionally failing to hand off back to the app
- In some cases requiring app restart or even device restart to recover
- Inconsistent behavior when switching between LAN, VPN, and remote access

Browser access (both local and via Nabu Casa) worked consistently, so the issue appears isolated to the mobile app’s connection/session handling.

**Workaround (Resolved):**
I created two separate server entries in the iOS app:

- One using the local URL (LAN)
- One using Nabu Casa (remote)

With this setup:

- The app reliably selects the correct endpoint based on reachability
- WebSocket connections remain stable
- No more connection drops or login issues
- No need to restart the app or device

**Feedback:**
It seems the auto-switching logic within a single server configuration may cause instability in environments with:

- VPN usage
- frequent network changes (LAN ↔ WAN)
- larger or more active HA setups

You may want to review:

- WebSocket reconnection handling
- auth handoff from webview → native app
- internal vs external URL switching logic within a single server profile

Happy to provide logs or test further if helpful.

Thanks!