Check if the room is valid before trying to refresh users

src/models/userlistmodel.cpp

@@ -163,6 +163,7 @@ void UserListModel::refreshAllUsers()
     }
     m_users.clear();
 
+    if (m_currentRoom != nullptr) {
         m_users = m_currentRoom->users();
         std::sort(m_users.begin(), m_users.end(), m_currentRoom->memberSorter());
 
@@ -174,6 +175,7 @@ void UserListModel::refreshAllUsers()
         connect(m_currentRoom->connection(), &Connection::loggedOut, this, [this]() {
             setRoom(nullptr);
         });
+    }
     endResetModel();
     Q_EMIT usersRefreshed();
 }