Resolved: “Authentication Required” Issue on Antigravity IDE

Google Antigravity
1

Screenshot 2026-01-22 162236

Hello everyone,

I also encountered the “Authentication Required” issue while using Antigravity IDE. While this solution may not apply to every case, it successfully resolved the problem for me.

:wrench: Solution

  • Switch to a different web browser (for example, from Chrome to Edge or Firefox)

  • Sign in to Antigravity IDE again

  • The authentication error was resolved immediately

:pushpin: Additional Notes

  • This method may also help with issues where no model is available for use

  • The root cause may be related to browser cache, cookies, or session conflicts

I hope this helps anyone facing the same issue.
If you have other solutions or insights, feel free to share.

2

In my case, I only needed to sign out of Antigravity IDE, close it, and then reopen it.
To sign out:
File > Preferences > Antigravity Settings (Ctrl + ,) > Account > Sign out.
If there is no response, check the profile/email account icon located just to the left of the minimize button (it looks like a dropdown button). Click that button. If it shows the message “not logged in,” it means you have already signed out. After that, close the IDE and reopen it.

4

In my case, the connection failure was caused by AVG Antivirus (specifically its Web Shield / HTTPS Scanning feature). AVG intercepts encrypted HTTPS traffic and replaces Google’s SSL certificates with its own local self-signed root certificate (AVG Web/Mail Shield Root), which Antigravity IDE’s internal Node.js runtime rejected by default.

[OAuth] Token exchange failed: request to https://oauth2.googleapis.com/token failed, reason: unable to verify the first certificate.