You are using a lower number of licenses internally than the total number, but TrueCommerce receives an error message that you have exceeded the total number of licensed users.
TrueCommerce is an external application, and it logs in as if it were an Everest user. As it operates, it creates a session in the system/database. If the external application is not logged out, then these sessions can add up and eventually exceed the number of licensed users, causing the error.
To solve this issue, please follow the steps described in the Logged-in users cause errors in SDK calls article.