diff --git a/src/api/health.ts b/src/api/health.ts
index 80a7c09..a4cac20 100644
--- a/src/api/health.ts
+++ b/src/api/health.ts
@@ -85,8 +85,18 @@ let confirmInFlight = false;
  * already shown.
  */
 export async function reportPossibleBackendDown(): Promise<void> {
-  if (confirmInFlight) return;
   if (useBlockingStore.getState().blockingType === 'backend_unavailable') return;
+  // During the INITIAL bootstrap (we've never reached the backend yet) the
+  // caller's failed request is itself the confirmation, so flip the screen
+  // IMMEDIATELY and synchronously. A deferred probe here would let the /login
+  // page paint for the ~probe duration before the outage screen — the "jump"
+  // we must avoid. Once the app has loaded, fall through to the confirm-probe so
+  // a one-off network blip can't blank a working session.
+  if (!everReachedBackend) {
+    useBlockingStore.getState().setBackendUnavailable();
+    return;
+  }
+  if (confirmInFlight) return;
   confirmInFlight = true;
   try {
     const reachable = await pingBackend();
@@ -97,3 +107,20 @@ export async function reportPossibleBackendDown(): Promise<void> {
     confirmInFlight = false;
   }
 }
+
+/**
+ * Eager liveness check fired once at app launch (from main.tsx), in parallel
+ * with auth bootstrap. If the backend is already down at launch this paints the
+ * ServiceUnavailableScreen immediately — before the auth flow can flash the
+ * /login page — even on the no-stored-token path that makes no early request.
+ * No-op if the app has already reached the backend or another blocking screen
+ * is showing.
+ */
+export async function checkBackendOnStartup(): Promise<void> {
+  if (everReachedBackend) return;
+  if (useBlockingStore.getState().blockingType !== null) return;
+  const reachable = await pingBackend();
+  if (!reachable && !everReachedBackend && useBlockingStore.getState().blockingType === null) {
+    useBlockingStore.getState().setBackendUnavailable();
+  }
+}
diff --git a/src/components/blocking/ServiceUnavailableScreen.tsx b/src/components/blocking/ServiceUnavailableScreen.tsx
index e5fa9a3..c60eadf 100644
--- a/src/components/blocking/ServiceUnavailableScreen.tsx
+++ b/src/components/blocking/ServiceUnavailableScreen.tsx
@@ -4,7 +4,8 @@ import { useQueryClient } from '@tanstack/react-query';
 import { useBlockingStore } from '../../store/blocking';
 import { useFocusTrap } from '../../hooks/useFocusTrap';
 import { pingBackend, hasEverReachedBackend } from '../../api/health';
-import { CloudWarningIcon, RestartIcon } from '@/components/icons';
+import { isInTelegramWebApp, closeTelegramApp } from '../../hooks/useTelegramSDK';
+import { CloudWarningIcon, RestartIcon, CloseIcon } from '@/components/icons';
 
 const POLL_INTERVAL_MS = 5000;
 
@@ -21,6 +22,7 @@ export default function ServiceUnavailableScreen() {
   const queryClient = useQueryClient();
   const [isChecking, setIsChecking] = useState(false);
   const isCheckingRef = useRef(false);
+  const inTelegram = isInTelegramWebApp();
 
   const recover = useCallback(() => {
     clearBlocking();
@@ -133,6 +135,18 @@ export default function ServiceUnavailableScreen() {
           )}
         </button>
 
+        {/* Close button — Telegram Mini App only (a browser tab can't be closed
+            by script). Reliably exits the Mini App instead of routing back. */}
+        {inTelegram && (
+          <button
+            onClick={closeTelegramApp}
+            className="mt-3 flex w-full items-center justify-center gap-2 rounded-xl border border-dark-700 px-6 py-4 font-semibold text-dark-300 transition-colors duration-200 hover:bg-dark-800 hover:text-white"
+          >
+            <CloseIcon className="h-5 w-5" />
+            {t('blocking.serviceUnavailable.close')}
+          </button>
+        )}
+
         {/* Decorative dots */}
         <div className="mt-8 flex items-center justify-center gap-2">
           <div
diff --git a/src/hooks/useTelegramSDK.ts b/src/hooks/useTelegramSDK.ts
index b2bc9f4..2a95b87 100644
--- a/src/hooks/useTelegramSDK.ts
+++ b/src/hooks/useTelegramSDK.ts
@@ -15,6 +15,8 @@ import {
   retrieveLaunchParams,
   retrieveRawInitData,
   themeParamsState,
+  closeMiniApp as sdkCloseMiniApp,
+  postEvent,
 } from '@telegram-apps/sdk-react';
 
 const FULLSCREEN_CACHE_KEY = 'cabinet_fullscreen_enabled';
@@ -50,6 +52,34 @@ export function isInTelegramWebApp(): boolean {
   return detectTelegram();
 }
 
+/**
+ * Closes the Telegram Mini App as reliably as possible. All three paths emit the
+ * same `web_app_close` event to the Telegram client; we try the most broadly
+ * compatible first and stop at the first that doesn't throw:
+ *   1) the legacy `window.Telegram.WebApp.close()` global (telegram-web-app.js,
+ *      loaded in index.html) — widest client coverage, no SDK-mount dependency;
+ *   2) the modern SDK `closeMiniApp()` (mini app is mounted on init);
+ *   3) the raw `postEvent('web_app_close')` protocol event — no global/mount
+ *      dependency at all.
+ * Outside Telegram it is a safe no-op.
+ */
+export function closeTelegramApp(): void {
+  try {
+    const wa = window.Telegram?.WebApp;
+    if (wa?.close) {
+      wa.close();
+      return;
+    }
+  } catch {}
+  try {
+    sdkCloseMiniApp();
+    return;
+  } catch {}
+  try {
+    postEvent('web_app_close');
+  } catch {}
+}
+
 export function isTelegramMobile(): boolean {
   try {
     const { tgWebAppPlatform } = retrieveLaunchParams();
diff --git a/src/locales/en.json b/src/locales/en.json
index 8243d4b..4f2a27b 100644
--- a/src/locales/en.json
+++ b/src/locales/en.json
@@ -4816,7 +4816,8 @@
       "description": "We can't reach the service right now. It may be undergoing maintenance or there's a temporary connection issue.",
       "retry": "Try again",
       "checking": "Checking connection...",
-      "hint": "This page will refresh automatically as soon as the service is back."
+      "hint": "This page will refresh automatically as soon as the service is back.",
+      "close": "Close"
     }
   },
   "merge": {
diff --git a/src/locales/fa.json b/src/locales/fa.json
index 82b72dc..fd2cc4d 100644
--- a/src/locales/fa.json
+++ b/src/locales/fa.json
@@ -4476,7 +4476,8 @@
       "description": "در حال حاضر امکان اتصال به سرویس وجود ندارد. ممکن است در حال تعمیر باشد یا مشکل موقتی در اتصال وجود داشته باشد.",
       "retry": "تلاش مجدد",
       "checking": "در حال بررسی اتصال...",
-      "hint": "به‌محض در دسترس قرار گرفتن سرویس، این صفحه به‌طور خودکار بازخوانی می‌شود."
+      "hint": "به‌محض در دسترس قرار گرفتن سرویس، این صفحه به‌طور خودکار بازخوانی می‌شود.",
+      "close": "بستن"
     }
   },
   "merge": {
diff --git a/src/locales/ru.json b/src/locales/ru.json
index 01fd8ab..672c5a1 100644
--- a/src/locales/ru.json
+++ b/src/locales/ru.json
@@ -5371,7 +5371,8 @@
       "description": "Не удаётся подключиться к сервису. Возможно, идут технические работы или временные неполадки со связью.",
       "retry": "Повторить попытку",
       "checking": "Проверяем соединение...",
-      "hint": "Страница обновится автоматически, как только сервис снова станет доступен."
+      "hint": "Страница обновится автоматически, как только сервис снова станет доступен.",
+      "close": "Закрыть"
     }
   },
   "merge": {
diff --git a/src/locales/zh.json b/src/locales/zh.json
index 19e7ca5..c196113 100644
--- a/src/locales/zh.json
+++ b/src/locales/zh.json
@@ -4357,7 +4357,8 @@
       "description": "暂时无法连接到服务。可能正在进行维护，或存在临时的网络问题。",
       "retry": "重试",
       "checking": "正在检查连接...",
-      "hint": "服务恢复后，本页面将自动刷新。"
+      "hint": "服务恢复后，本页面将自动刷新。",
+      "close": "关闭"
     }
   },
   "banSystem": {
diff --git a/src/main.tsx b/src/main.tsx
index 7e61769..022c153 100644
--- a/src/main.tsx
+++ b/src/main.tsx
@@ -24,6 +24,7 @@ import { useAuthStore } from './store/auth';
 import { AppWithNavigator } from './AppWithNavigator';
 import { ErrorBoundary } from './components/ErrorBoundary';
 import { initLogoPreload } from './api/branding';
+import { checkBackendOnStartup } from './api/health';
 import { getCachedFullscreenEnabled, isTelegramMobile } from './hooks/useTelegramSDK';
 import { applyTelegramLanguage } from './i18n';
 import './styles/globals.css';
@@ -106,6 +107,11 @@ if (isTelegramEnv && !alreadyInitialized) {
 // are only available post-init()).
 void useAuthStore.getState().initialize();
 
+// In parallel with auth bootstrap, eagerly check backend liveness so a dead
+// backend paints the ServiceUnavailableScreen immediately instead of flashing
+// the /login page first.
+void checkBackendOnStartup();
+
 if ('requestIdleCallback' in window) {
   requestIdleCallback(() => initLogoPreload());
 } else {
diff --git a/src/vite-env.d.ts b/src/vite-env.d.ts
index 50297fe..a05d633 100644
--- a/src/vite-env.d.ts
+++ b/src/vite-env.d.ts
@@ -19,6 +19,8 @@ interface ImportMeta {
 interface TelegramWebAppGlobal {
   onEvent?: (event: string, callback: () => void) => void;
   offEvent?: (event: string, callback: () => void) => void;
+  /** Closes the Mini App (injected by telegram-web-app.js). */
+  close?: () => void;
 }
 
 /** Telegram Login JS SDK — loaded from https://oauth.telegram.org/js/telegram-login.js */