diff --git a/frontend/src/providers/AuthProvider.tsx b/frontend/src/providers/AuthProvider.tsx
index a0f6242..03c0afe 100644
--- a/frontend/src/providers/AuthProvider.tsx
+++ b/frontend/src/providers/AuthProvider.tsx
@@ -56,7 +56,7 @@ import React, {
 } from "react";
 import { useNavigate } from "react-router-dom";
 import * as authApi from "../api/auth";
-import { setUnauthorizedHandler, resetLogoutState, clearSessionCorrelationId } from "../api/client";
+import { ApiError, setUnauthorizedHandler, resetLogoutState, clearSessionCorrelationId } from "../api/client";
 import { setAuthErrorHandler, resetLogoutState as resetFetchErrorLogoutState } from "../utils/fetchError";
 import { STORAGE_KEY_AUTHENTICATED } from "../utils/constants";
 import { SessionValidationLoading } from "../components/SessionValidationLoading";
@@ -133,6 +133,11 @@ export function AuthProvider({
 
   const handleValidationError = useCallback(
     (error: Error): void => {
+      // Suppress noisy warning for 5xx gateway errors (e.g. 502 Bad Gateway)
+      // during startup — these are server-side issues, not network issues.
+      if (error instanceof ApiError && error.status >= 500) {
+        return;
+      }
       // Network error — log but don't logout.
       console.warn("Session validation network error:", error);
     },