Shortcuts 'Call Service' returns 404 on cellular, works on WiFi

[ericmason]

iOS device model, version and app version

Model Name: iPhone 16
Software Version: iOS 26.3.0
App version: 2026.1.1 (build 1652)

Home Assistant Core Version

2026.2.1

Describe the bug

iOS Shortcuts using the "Call Service" action fail with a 404 error when triggered on cellular (5G). The same Shortcuts work correctly on WiFi. This started recently, likely coinciding with the HA Core 2026.2 update.

The error message displayed is:

"Failed: Error during api.callService: Unacceptable status code 404."

The Home Assistant app itself works fine on cellular — WebSocket connects, dashboard loads, entities are accessible. Only the Shortcuts integration is broken on cellular.

Nginx access logs show webhook POST requests when Shortcuts are triggered on WiFi, but zero requests reach the server when triggered on cellular. This suggests the Shortcuts/Intents extension is either not sending the request or sending it to the wrong destination when off WiFi.

The external URL is confirmed reachable from cellular — Safari loads the HA login page, and the app itself connects via WebSocket and shows "Connected via: External URL" with "WebSocket: Connected".

To Reproduce

1. Configure HA companion app with only an external URL (no internal URL set)
2. Create an iOS Shortcut using the HA "Call Service" action (e.g., lock.unlock)
3. Run the Shortcut while connected to WiFi → works (200/201 in server logs)
4. Switch to cellular (5G) and run the same Shortcut → fails with 404
5. Confirm the HA app itself works on cellular (WebSocket connected, dashboard loads)

Expected behavior

Shortcuts should work on both WiFi and cellular, as they did prior to the recent updates.

Additional context

• Internal URL: not configured (set to —)
• External URL: configured and working via HTTPS
• Reverse proxy: nginx
• Connection security level: Most secure
• iCloud Private Relay: disabled
• Port 443 confirmed open externally
• The key observation is that no HTTP requests reach the server at all when the Shortcut runs on cellular — this is not a server-side 404, it appears the Shortcuts extension fails to dispatch the request when off WiFi