diff --git a/Clone App/Instagram/Instagram.xcworkspace/xcuserdata/yangseunghyeon.xcuserdatad/xcdebugger/Expressions.xcexplist b/Clone App/Instagram/Instagram.xcworkspace/xcuserdata/yangseunghyeon.xcuserdatad/xcdebugger/Expressions.xcexplist
index b40c5435..ba841b5d 100644
--- a/Clone App/Instagram/Instagram.xcworkspace/xcuserdata/yangseunghyeon.xcuserdatad/xcdebugger/Expressions.xcexplist	
+++ b/Clone App/Instagram/Instagram.xcworkspace/xcuserdata/yangseunghyeon.xcuserdatad/xcdebugger/Expressions.xcexplist	
@@ -38,5 +38,13 @@
             </PersistentString>
          </PersistentStrings>
       </ContextState>
+      <ContextState
+         contextName = "closure #1 in MainHomeTabController.authenticationCompletion():MainHomeTabController.swift">
+         <PersistentStrings>
+            <PersistentString
+               value = "userInfo">
+            </PersistentString>
+         </PersistentStrings>
+      </ContextState>
    </ContextStates>
 </VariablesViewState>
diff --git a/Clone App/Instagram/Instagram/Controller/FeedController.swift b/Clone App/Instagram/Instagram/Controller/FeedController.swift
index 16382e48..39f41711 100644
--- a/Clone App/Instagram/Instagram/Controller/FeedController.swift	
+++ b/Clone App/Instagram/Instagram/Controller/FeedController.swift	
@@ -10,14 +10,17 @@ import Firebase
 
 class FeedController: UICollectionViewController {
     
-    private let reuseIdentifier = "FeedCell"
     
     //MARK: - LifeCycle
     override func viewDidLoad() {
         super.viewDidLoad()
-        collectionView.register(FeedCell.self, forCellWithReuseIdentifier: reuseIdentifier  )
+        collectionView.register(FeedCell.self, forCellWithReuseIdentifier: FEEDCELLRESUIDENTIFIER  )
+    }
+    
+    override func viewWillAppear(_ animated: Bool) {
+        super.viewWillAppear(animated)
+        collectionView.register(FeedCell.self, forCellWithReuseIdentifier: FEEDCELLRESUIDENTIFIER)
         setupNavigationUI()
-        
     }
 }
 
@@ -50,7 +53,7 @@ extension FeedController {
     }
     
     override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
-        guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath) as? FeedCell else {
+        guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: FEEDCELLRESUIDENTIFIER, for: indexPath) as? FeedCell else {
             fatalError()
         }
         
diff --git a/Clone App/Instagram/Instagram/Controller/MainHomeTabController.swift b/Clone App/Instagram/Instagram/Controller/MainHomeTabController.swift
index 02559a3f..0898844c 100644
--- a/Clone App/Instagram/Instagram/Controller/MainHomeTabController.swift	
+++ b/Clone App/Instagram/Instagram/Controller/MainHomeTabController.swift	
@@ -17,10 +17,26 @@ class MainHomeTabController: UITabBarController {
         }
     }
     
+    private var isLogin: Bool? {
+        didSet {
+            guard let isLogin = isLogin else { return }
+            if !isLogin {
+                DispatchQueue.main.async {
+                    self.presentLoginScene()
+                }
+            }
+        }
+    }
+    
+    
     //MARK: - Lifecycle
     override func viewDidLoad() {
         super.viewDidLoad()
         view.backgroundColor = .white
+    }
+    
+    override func viewWillAppear(_ animated: Bool) {
+        super.viewWillAppear(animated)
         configure()
         
     }
@@ -29,15 +45,14 @@ class MainHomeTabController: UITabBarController {
         configure()
     }
     
-}
+} 
 
 //MARK: - Helpers
 extension MainHomeTabController {
     
     func configure() {
         customTabBarUI()
-        fetchUserInfo()
-        checkIfUserIsLoggedIn()
+        isLogin = isUserLogined()
     }
     
     func configureViewControllers() {
@@ -53,7 +68,7 @@ extension MainHomeTabController {
         
         let notifications = templateNavigationController(unselectedImage: .imageLiteral(name: "like_unselected"), selectedImage: .imageLiteral(name: "like_selected"), rootVC: NotificationController())
         
-        var profileVC = ProfileController(user: userVM.getUserInfoModel())
+        let profileVC = ProfileController(user: userVM.getUserInfoModel())
         UserService.fetchUserProfile(userProfile: userVM.getUserProfileURL()) { image in
             profileVC.profileImage = image
         }
@@ -122,13 +137,16 @@ extension MainHomeTabController {
     
     
     //MARK: - API. check user's membership
-    func checkIfUserIsLoggedIn() {
-        if CURRENT_USER == nil {
-            self.view.isHidden = true
-            self.presentLoginScene()
+    func isUserLogined() -> Bool {
+        if Auth.auth().currentUser == nil {
+            return false
         }
+        fetchUserInfo()
+        return true
     }
     
+    
+    
     func presentLoginScene() {
         let controller = LoginController()
         controller.authDelegate = self
@@ -143,9 +161,12 @@ extension MainHomeTabController {
 //MARK: - Implement AuthentificationDelegate
 extension MainHomeTabController: AuthentificationDelegate {
     func authenticationCompletion() {
-        fetchUserInfo()
+        UserService.fetchCurrentUserInfo() { userInfo in
+            guard let userInfo = userInfo else { return }
+            self.viewDidLoad()
+            self.userVM = UserInfoViewModel(user: userInfo, profileImage: nil)
+        }
         self.dismiss(animated: false)
     }
     
-    
 }
diff --git a/Clone App/Instagram/Instagram/Utils/Constants.swift b/Clone App/Instagram/Instagram/Utils/Constants.swift
index 390862e5..76076683 100644
--- a/Clone App/Instagram/Instagram/Utils/Constants.swift	
+++ b/Clone App/Instagram/Instagram/Utils/Constants.swift	
@@ -20,3 +20,8 @@ let AUTH = Auth.auth()
 //MARK: - profile subview's ID
 let COLLECTIONHEADERREUSEABLEID = "UserProfileCollectionHeaderView"
 let CELLREUSEABLEID = "CollectionViewCell"
+
+
+//MARK:  - FeedVieController subview's ID
+
+let FEEDCELLRESUIDENTIFIER = "FeedCell"