Hi Wolfgang,
The current setting allows for a maximum of 50 users to be created at any given time. This means that for example, you can create 50 users, then delete them all and create an additional 50.
However, it's important to understand that inactive users still count towards this limit. So if, for instance, you have 50 users registered and 10 of them are inactive, you will not be able to create additional users until you remove some from your current pool.
Should you find it necessary to increase this limit, this would need to be discussed with your security engineer, as it involves getting special approval.