Lito Yap
Ansys Employee

@Silvie Luisa Brázdilová, 

The license being checkout/checkin when the simulation starts and finishes is intended. You can "reserve" the license as shown in this Knowledge Base (KB) page

Based on your entitlement/records, you have a commercial license. For commercial license users, please register with Lumerical support. And submit a ticket through the Lumerical/Optics support portal. Thank you.