diff --git a/src/App.tsx b/src/App.tsx
index 6e1a19cb1..e72b669f6 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -1,25 +1,42 @@
 import { FC, useEffect } from './lib/teact/teact';
 import React, { withGlobal } from './lib/teact/teactn';
 
-import { GlobalState } from './global/types';
+import { GlobalActions, GlobalState } from './global/types';
 
+import { INACTIVE_MARKER, PAGE_TITLE } from './config';
 import { pick } from './util/iteratees';
 import { updateSizes } from './util/windowSize';
+import { addActiveTabChangeListener } from './util/activeTabMonitor';
+import useFlag from './hooks/useFlag';
 
 import Auth from './components/auth/Auth';
 import UiLoader from './components/common/UiLoader';
 import Main from './components/main/Main.async';
+import AppInactive from './components/main/AppInactive';
 // import Test from './components/test/TestNoRedundancy';
 
 type StateProps = Pick<GlobalState, 'authState' | 'authIsSessionRemembered'>;
+type DispatchProps = Pick<GlobalActions, 'disconnect'>;
+
+const App: FC<StateProps & DispatchProps> = ({ authState, authIsSessionRemembered, disconnect }) => {
+  const [isInactive, markInactive] = useFlag(false);
 
-const App: FC<StateProps> = ({ authState, authIsSessionRemembered }) => {
   useEffect(() => {
     updateSizes();
-  }, []);
+    addActiveTabChangeListener(() => {
+      disconnect();
+      document.title = `${PAGE_TITLE}${INACTIVE_MARKER}`;
+
+      markInactive();
+    });
+  }, [disconnect, markInactive]);
 
   // return <Test />;
 
+  if (isInactive) {
+    return <AppInactive />;
+  }
+
   if (authState) {
     switch (authState) {
       case 'authorizationStateWaitPhoneNumber':
@@ -49,4 +66,5 @@ function renderMain() {
 
 export default withGlobal(
   (global): StateProps => pick(global, ['authState', 'authIsSessionRemembered']),
+  (setGlobal, actions): DispatchProps => pick(actions, ['disconnect']),
 )(App);
diff --git a/src/api/gramjs/methods/client.ts b/src/api/gramjs/methods/client.ts
index b708ff0c7..901b01723 100644
--- a/src/api/gramjs/methods/client.ts
+++ b/src/api/gramjs/methods/client.ts
@@ -95,6 +95,10 @@ export async function destroy() {
   await client.destroy();
 }
 
+export async function disconnect() {
+  await client.disconnect();
+}
+
 export function getClient() {
   return client;
 }
diff --git a/src/api/gramjs/methods/index.ts b/src/api/gramjs/methods/index.ts
index 493f05305..6ae1d87cd 100644
--- a/src/api/gramjs/methods/index.ts
+++ b/src/api/gramjs/methods/index.ts
@@ -1,4 +1,6 @@
-export { destroy, downloadMedia, fetchCurrentUser } from './client';
+export {
+  destroy, disconnect, downloadMedia, fetchCurrentUser,
+} from './client';
 
 export {
   provideAuthPhoneNumber, provideAuthCode, provideAuthPassword, provideAuthRegistration, restartAuth, restartAuthWithQr,
diff --git a/src/assets/app-inactive.png b/src/assets/app-inactive.png
new file mode 100644
index 000000000..f2878d7fe
Binary files /dev/null and b/src/assets/app-inactive.png differ
diff --git a/src/components/main/AppInactive.scss b/src/components/main/AppInactive.scss
new file mode 100644
index 000000000..e2dad3c4f
--- /dev/null
+++ b/src/components/main/AppInactive.scss
@@ -0,0 +1,32 @@
+#AppInactive {
+  height: 100%;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+
+  .content {
+    max-width: 28rem;
+    margin: auto;
+    padding: 1.5rem;
+    text-align: center;
+  }
+
+  .title {
+    margin-top: 1rem;
+  }
+
+  .description {
+    color: var(--color-text-secondary);
+    font-size: 0.875rem;
+  }
+
+  img {
+    width: 100%;
+    max-width: 20rem;
+  }
+
+  .Button {
+    margin-top: 1rem;
+  }
+}
diff --git a/src/components/main/AppInactive.tsx b/src/components/main/AppInactive.tsx
new file mode 100644
index 000000000..b9c68fbb9
--- /dev/null
+++ b/src/components/main/AppInactive.tsx
@@ -0,0 +1,32 @@
+import React, { FC } from '../../lib/teact/teact';
+
+import Button from '../ui/Button';
+
+import appInactivePath from '../../assets/app-inactive.png';
+import './AppInactive.scss';
+
+
+const AppInactive: FC = () => {
+  const handleReload = () => {
+    window.location.reload();
+  };
+
+  return (
+    <div id="AppInactive">
+      <div className="content">
+        <img src={appInactivePath} alt="" />
+        <h3 className="title">Such error, many tabs</h3>
+        <div className="description">
+          Telegram supports only one active tab with the app.
+          <br />
+          Please reload this page to continue using this tab or close it.
+        </div>
+        <div className="actions">
+          <Button isText ripple onClick={handleReload}>Reload app</Button>
+        </div>
+      </div>
+    </div>
+  );
+};
+
+export default AppInactive;
diff --git a/src/components/main/Main.tsx b/src/components/main/Main.tsx
index 6bb0d2a8a..0a8e46ae5 100644
--- a/src/components/main/Main.tsx
+++ b/src/components/main/Main.tsx
@@ -5,7 +5,9 @@ import { GlobalActions } from '../../global/types';
 import { ApiMessage } from '../../api/types';
 
 import '../../modules/actions/all';
-import { ANIMATION_END_DELAY, DEBUG } from '../../config';
+import {
+  ANIMATION_END_DELAY, DEBUG, INACTIVE_MARKER, PAGE_TITLE,
+} from '../../config';
 import { pick } from '../../util/iteratees';
 import {
   selectChatMessage,
@@ -44,7 +46,6 @@ type StateProps = {
 
 type DispatchProps = Pick<GlobalActions, 'loadAnimatedEmojis'>;
 
-const APP_NAME = 'Telegram';
 const ANIMATION_DURATION = 350;
 const NOTIFICATION_INTERVAL = 1000;
 
@@ -122,6 +123,11 @@ const Main: FC<StateProps & DispatchProps> = ({
 
     clearInterval(notificationInterval);
     notificationInterval = window.setInterval(() => {
+      if (document.title.includes(INACTIVE_MARKER)) {
+        updateIcon(false);
+        return;
+      }
+
       if (index % 2 === 0) {
         const newUnread = selectCountNotMutedUnread(getGlobal()) - initialUnread;
         if (newUnread > 0) {
@@ -129,7 +135,7 @@ const Main: FC<StateProps & DispatchProps> = ({
           updateIcon(true);
         }
       } else {
-        document.title = APP_NAME;
+        document.title = PAGE_TITLE;
         updateIcon(false);
       }
 
@@ -138,7 +144,11 @@ const Main: FC<StateProps & DispatchProps> = ({
   }, () => {
     clearInterval(notificationInterval);
     notificationInterval = undefined;
-    document.title = APP_NAME;
+
+    if (!document.title.includes(INACTIVE_MARKER)) {
+      document.title = PAGE_TITLE;
+    }
+
     updateIcon(false);
   });
 
diff --git a/src/config.ts b/src/config.ts
index 8899f3b53..7c877233a 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -1,3 +1,6 @@
+export const PAGE_TITLE = 'Telegram';
+export const INACTIVE_MARKER = ' [Inactive]';
+
 export const APP_INFO = process.env.APP_INFO || 'Telegram T';
 
 export const DEBUG = (
diff --git a/src/global/types.ts b/src/global/types.ts
index 0ecba995a..43f13da82 100644
--- a/src/global/types.ts
+++ b/src/global/types.ts
@@ -383,7 +383,7 @@ export type GlobalState = {
 
 export type ActionTypes = (
   // system
-  'init' | 'reset' | 'initApi' | 'apiUpdate' | 'sync' | 'saveSession' | 'afterSync' |
+  'init' | 'reset' | 'disconnect' | 'initApi' | 'apiUpdate' | 'sync' | 'saveSession' | 'afterSync' |
   'showNotification' | 'dismissNotification' | 'showError' | 'dismissError' |
   // ui
   'toggleChatInfo' | 'setIsUiReady' | 'addRecentEmoji' | 'addRecentSticker' | 'toggleLeftColumn' |
diff --git a/src/modules/actions/api/initial.ts b/src/modules/actions/api/initial.ts
index 30e2eac41..287cc723f 100644
--- a/src/modules/actions/api/initial.ts
+++ b/src/modules/actions/api/initial.ts
@@ -126,6 +126,12 @@ addReducer('reset', () => {
   getDispatch().init();
 });
 
+addReducer('disconnect', () => {
+  (async () => {
+    await callApi('disconnect');
+  })();
+});
+
 addReducer('loadNearestCountry', (global) => {
   if (global.connectionState !== 'connectionStateReady') {
     return;
diff --git a/src/util/activeTabMonitor.ts b/src/util/activeTabMonitor.ts
new file mode 100644
index 000000000..96c5535ff
--- /dev/null
+++ b/src/util/activeTabMonitor.ts
@@ -0,0 +1,19 @@
+const STORAGE_KEY = 'tt-active-tab';
+const INTERVAL = 2000;
+
+const tabKey = String(Date.now() + Math.random());
+
+localStorage.setItem(STORAGE_KEY, tabKey);
+
+let callback: NoneToVoidFunction;
+
+const interval = window.setInterval(() => {
+  if (callback && localStorage.getItem(STORAGE_KEY) !== tabKey) {
+    callback();
+    clearInterval(interval);
+  }
+}, INTERVAL);
+
+export function addActiveTabChangeListener(_callback: NoneToVoidFunction) {
+  callback = _callback;
+}