[Windows][2.17.0] language_server.exe ignores system proxy during startup, causing infinite Loading / black screen

Google Antigravity
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1

Description:
On Windows, Antigravity 2.17.0 can get stuck indefinitely on the “Loading Antigravity” screen and eventually show a black window.

Investigation shows that language_server.exe successfully starts and listens on a local HTTPS port (for example 127.0.0.1:55654), but the local service does not respond to HTTP/HTTPS requests during initialization.

At the same time, language_server.exe attempts to connect directly to Google services. These outbound connections remain stuck in SYN_SENT.

Windows system proxy is enabled and points to a working Mihomo HTTP proxy at 127.0.0.1:7897. The same Google endpoints are reachable successfully through that proxy.

However, the Antigravity backend / language_server.exe does not appear to use the Windows system proxy during startup.

Reproduction / isolation testing:

  1. Start Antigravity normally with Windows system proxy enabled.
  2. Antigravity remains on the Loading screen.
  3. Electron eventually logs:
    Failed to load URL: 27.0.0.1 :confused: with error: ERR_TIMED_OUT
  4. The local port is already in LISTENING state, but requests receive no response.
  5. The issue still occurs with:
    –user-data-dir
    –disable-extensions
    –disable-gpu
  6. Start Antigravity again with explicit process environment variables:
    HTTP_PROXY=127.0.0.1:7897
    HTTPS_PROXY=127.0.0.1:7897
  7. language_server.exe completes initialization, the local page returns HTTP 200, and Antigravity starts normally.

Expected behavior:
Antigravity’s backend processes should respect the Windows system proxy, or inherit / properly propagate the proxy configuration used by the Electron application.

Actual behavior:
language_server.exe attempts direct outbound connections during initialization. When direct access to the required Google services is unavailable, backend initialization stalls and the local UI server never becomes ready, causing Electron to time out and Antigravity to remain stuck on Loading / black screen.

Workaround:
Launch Antigravity with HTTP_PROXY and HTTPS_PROXY explicitly set for the Antigravity process.

No changes to extensions, GPU settings, cache, WSL, user data, or projects are required.

Environment:

  • Windows
  • Antigravity 2.17.0
  • Windows system proxy enabled
  • Local proxy: Mihomo
  • Proxy endpoint: 127.0.0.1:7897
  • Reproduced with a clean temporary user-data directory