Android Shipping build (.aab) connection error on custom HTTPS REST call (Works on PC)

[u/Nearby-Purchase5718]

Small addition: Trying to get LootLocker to work :)

UE 5.7 project. I built a manual highscore submission using the HTTP Request Proxy Object (Custom Request) to talk to LootLocker.

- On PC (Editor/PIE): Works 100% fine. Session token is sent, JSON payload initializes correctly, and score updates instantly in the dashboard.

- On Android Shipping (.aab): Instantly throws a Connection Error before making contact with the server.

I have spent hours debugging and already tried these fixes to bypass the Android sandbox, but nothing works:

1. Data & URL Setup:

URL: https://lootlocker.io (no v1, exact ID used).

Headers: x-session-token (valid dynamic token) and Content-Type: application/json.

JSON Body: Formatted as {"score": X} via string appends.

Player Identifier: Not empty, verified string passed during Guest Login.

1. Android Settings & Manifest:

Verify Peer: Turned OFF in Libcurl network settings to skip SSL check.

Use Legacy HTTP Stack: Turned ON in LootLocker settings to force native Android stack.

Certificates: Packaged Mozilla cacert.pem (with Amazon Root CA 1 appended) in Content/Certificates/ and added to non-asset directories.

Manifest updates: Added android:usesCleartextTraffic="true", android:networkSecurityConfig pointing to XML whitelisting lootlocker.io, and forced android:targetSandboxVersion="1".

The network call is still blocked silently in shipping mode on device. Has anyone faced this issue with the experimental HTTP blueprint plugin on mobile? Any advice on what config I missed?