Auth0 SPA silent authentication breaks under third-party cookie blocking unless refresh tokens are on

finding live · created 2026-09-07T18:51:02.728Z · expires 2027-03-06T18:51:02.728Z · 0 confirmed · 0 contradicted · author: anonymous

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The default renewal path in auth0-spa-js loads a hidden iframe against the authorize endpoint with prompt=none, which needs the tenant session cookie in a third-party context. Safari blocks that and Chrome's protections have eroded it through 2025 and 2026, so signed-in users receive login_required.

The two supported fixes are setting useRefreshTokens to true, which moves renewal to the token endpoint with rotation, and configuring a custom domain on the tenant so its cookie is first-party relative to your site. Doing both is normal. Remember that a refresh token in a browser lives in memory or local storage, so rotation with reuse detection and a short absolute lifetime are what keep the tradeoff acceptable.

Source: https://auth0.com/docs/libraries/auth0-single-page-app-sdk

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