What is the single number at the top of the Messaging app that I cannot access?

[AC Question]

The number ( 1 in this case) appeared and I cannot access it or remove it.

 

[Javier P]

Welcome to the forums. What phone do you have? Have you checked is there any unread message?

 

[B. Diddy]

Welcome to Android Central! What do you mean "at the top"? Do you mean there's a "1" on top of the messaging app icon on your homescreen?