When adding doors to Tenant or change the number of individuals in Tenant editor, there is always an error that the change can't be saved.
The maximum individuals for one door in DPU7920 with DPU48K and SCU 1284 with firmware newer than 3.24 is 64000.
Try to decrease the individual number for the door within 64000. Do not forget the Tenant disabled. The individual number of disabled Tenant for a door is also inclusive in this 64000. Refer to Lessons Learned article #6335 for more details about the individual number limit for the door controller.