diff --git a/api/src/Kurs.Platform.HttpApi.Host/Classroom/ClassroomHub.cs b/api/src/Kurs.Platform.HttpApi.Host/Classroom/ClassroomHub.cs
index b34dd59b..f577a41a 100644
--- a/api/src/Kurs.Platform.HttpApi.Host/Classroom/ClassroomHub.cs
+++ b/api/src/Kurs.Platform.HttpApi.Host/Classroom/ClassroomHub.cs
@@ -114,7 +114,8 @@ public class ClassroomHub : Hub
         }
 
         await Clients.Group(sessionId.ToString())
-            .SendAsync("ParticipantLeft", _currentUser);
+            .SendAsync("ParticipantLeft", _currentUser.Id.ToString());
+            
         _logger.LogInformation($"User {_currentUser} left class {sessionId}");
     }
 
diff --git a/ui/src/components/classroom/VideoPlayer.tsx b/ui/src/components/classroom/VideoPlayer.tsx
index d5b2f1a2..793bb45e 100644
--- a/ui/src/components/classroom/VideoPlayer.tsx
+++ b/ui/src/components/classroom/VideoPlayer.tsx
@@ -1,7 +1,6 @@
 import React, { useRef, useEffect } from 'react'
 import { FaMicrophoneSlash, FaVideoSlash } from 'react-icons/fa'
 
-// VideoOff component replacement
 const VideoOff: React.FC<{ size?: number; className?: string }> = ({
   size = 24,
   className = '',
@@ -31,8 +30,19 @@ export const VideoPlayer: React.FC<VideoPlayerProps> = ({
   const videoRef = useRef<HTMLVideoElement>(null)
 
   useEffect(() => {
-    if (videoRef.current && stream) {
-      videoRef.current.srcObject = stream
+    const videoEl = videoRef.current
+    if (!videoEl) return
+
+    if (stream) {
+      videoEl.srcObject = stream
+    } else {
+      videoEl.srcObject = null // 🟢 ayrıldığında video siyaha düşer
+    }
+
+    return () => {
+      if (videoEl) {
+        videoEl.srcObject = null // 🟢 cleanup
+      }
     }
   }, [stream])
 
diff --git a/ui/src/views/classroom/RoomDetail.tsx b/ui/src/views/classroom/RoomDetail.tsx
index d2182997..5dd5c083 100644
--- a/ui/src/views/classroom/RoomDetail.tsx
+++ b/ui/src/views/classroom/RoomDetail.tsx
@@ -266,17 +266,15 @@ const RoomDetail: React.FC = () => {
 
       // Setup SignalR event handlers
       signalRServiceRef.current.setParticipantJoinHandler(async (userId, name) => {
-        // 🔑 Eğer gelen participant bizsek, listeye ekleme
         if (userId === user.id) return
 
         console.log(`Participant joined: ${name}`)
 
-        // Create WebRTC connection for new participant
         if (webRTCServiceRef.current) {
           webRTCServiceRef.current.createPeerConnection(userId)
 
-          // Eğer biz teacher isek offer oluşturup gönderelim
-          if (user.role === 'teacher') {
+          // ✅ Sadece teacher offer gönderecek
+          if (user.role === 'student') {
             const offer = await webRTCServiceRef.current.createOffer(userId)
             await signalRServiceRef.current?.sendOffer(classSession.id, userId, offer)
           }
@@ -300,8 +298,12 @@ const RoomDetail: React.FC = () => {
 
       signalRServiceRef.current.setParticipantLeaveHandler((userId) => {
         console.log(`Participant left: ${userId}`)
-        setParticipants((prev) => prev.filter((p) => p.id !== userId))
+
+        // peer connection’ı kapat
         webRTCServiceRef.current?.closePeerConnection(userId)
+
+        // katılımcıyı state’den sil
+        setParticipants((prev) => prev.filter((p) => p.id !== userId))
       })
 
       signalRServiceRef.current.setAttendanceUpdatedHandler((record) => {