If you notice that your 4D Server is hitting the maximum number of used licenses earlier than expected, it is recommended to verify on the Administration window whether you may have additional 4D REST clients that have accessed an endpoint some point in time while the web server was live. 4D REST clients are treated the same as any other connected user and if part of the 4D Client Expansion program, these REST clients are not intended for in-n-out access.

If you are considering heavy usage of 4D REST, it is highly recommended to consider a Web Application license that allows unlimited connections to your 4D web server that can alleviate this situation.