Antigravity login completes in browser but app fails with “Failed to exchange authorization code for token”

Google Antigravity
1

Environment:

  • OS: Windows 11

  • Antigravity: latest version downloaded from official site

  • Browsers tested: Brave, Edge, Chrome

  • Network: no VPN

  • Firewall test: disabled for testing

  • Multiple Google accounts tested

  • Reinstalled app

  • Ran app as administrator

  • Deep link protocol works: antigravity:// opens the app

Observed behavior:

  • Click “Sign in with Google”

  • Browser opens

  • Google login succeeds

  • Browser shows success page: https://antigravity.google/auth-success?app=antigravity

  • Browser also prompts to open Antigravity, and opening the app works

  • Antigravity then shows: “There was an unexpected issue setting up your account. Failed to exchange authorization code for token”

Relevant logs:

  • [BrowserOnboardingClientServer] Browser onboarding server started on http://localhost:53090

  • Also reproduced on random port:

  • [BrowserOnboardingClientServer] Browser onboarding server started on http://localhost:65159

  • Clearing HTTP_PROXY, HTTPS_PROXY, ALL_PROXY and setting NO_PROXY=localhost,127.0.0.1 did not fix it

  • antigravity:// opens the app successfully

  • CheckNetIsolation LoopbackExempt -s shows no relevant exemption issue

  • netstat -ano | findstr <port> did not show a conflicting listener after the fact

What I already tried:

  • Brave shields off / allow all cookies

  • Edge and Chrome

  • Always allow opening Antigravity from browser

  • Run as admin

  • Reinstall

  • Different Google account

  • Disable firewall

  • Clear proxy env vars

Request:
Please confirm whether this is a known regression in the Windows desktop client / OAuth token exchange flow and whether there is a patched build or workaround.