Hi Hùng, 

Welcome to Box Community and glad to assist! 

 Are you signed in to the same Box account that the collaboration invite was sent to? To rectify this, please follow the instructions below. 

1. 
   

   Confirm which email the invitation is being sent to.

   
   


2. 
   

   Check which email address your Box account is associated to. To do so, go to your Box account, click on your name on the top right hand side, then navigate to "Account Settings."

   
   


3. 
   

   Make sure the email address the invitation was sent to matches the email in your account settings.

   
   


4. 
   

   If they do not match, have the invitation sent to the email associated with the Box account.

   
   

You can find this information via this article. 

Thanks for posting! 

This happened with my old account that I had been using. The issue only occurred after logging in again.