Sandbox OAuth authorize page renders blank (empty #root) — app config verified correct

Our sandbox OAuth authorize flow is stuck on a blank white page. Endpoint: squareupsandbox dot com/oauth2/authorize with client_id sandbox-sq0idb-LS1d6e7fIzICamMFT9aZ-A. The page’s JS/CSS assets load successfully, but the #root container never renders any content (0 child elements) - no login form, no consent screen, nothing. Reproduced consistently across fresh page loads, incognito mode, and brand new state tokens/minimal query params (removing state and session=false didn’t help). App config (redirect URI, scopes, client_id) all verified correct in the Developer Console, and using the console’s own “Authorize test account” shortcut works fine and issues valid tokens - so this appears isolated to the hosted authorize page’s front-end rendering, not our app setup. Can someone from the team take a look?

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Hello, Check if the sandbox URL has a trailing slash or missing redirect_uri mismatchthose are the most common causes of a blank white page in the OAuth authorize flow. Milestone Card