Just before 5 minutes my all notification removed by themselves. There isn't a single notification showing there. As well as the group chats also removed themselves. I have signout and sign in again but it's the same. Is this happening for you all? Check the problem which is occurring here.
So please help me!
Thanks to all who helped me.
Now the problem is resolved from my side too. I was being in hurry because all the notification flown away. Thanks to the moderator and coders who helped me in this situation. Now it's totally RESOLVED!