So I manage a very small network of let's say 200 users. We all work in a municipal building and we pay for our own private internet. The internet feeds a WiFi network that consists of Apple airport devices on 4 floors. It all feeds back to the TL-R480T+ router. 
 

I have enabled the captive portal in the router to use to authenticate users to use the network. I am using the built in portal that comes with the router. 
 

The problem I am having is users are having no problems logging in and authenticating with the router. After a few days when they log back in they get a message that their user name is already using the maximum number of users. 
 

I created a user list and have set each user for dynamic binding so it captures their MAC. 
 

has anyone seen this type of issue?