Fix login errors

src/Client/src/app/services/Authentication.ts

@@ -31,7 +31,7 @@ export class Authentication{
     }
 
     get isLoggedIn(): boolean {
-        return this._user.value.id != -1 ? true : false;
+        return this._user.value.id == null ? true : false;
     }
 
     get loggedInUser(): Account {

src/Server/Controllers/AuthenticationController.cs

@@ -43,7 +43,7 @@ namespace BoredCareers.Controllers {
                 signOut();
                 return Redirect("/");
             }
-            return NotFound();
+            return NotFound("Not logged in");
         }
 
     }