Nextcloud does not show the entire hard drive as storage space

Hi, i use a 500GB SSD for a Nextcloudinstallation via snap. Nothing else installed. But i can only use 100GB. Under “System” i found this:
Storage: 5 Free storage: 71 GB. The used storage is about 30GB. There is one more user with about 5 GB. The contingent is set for both on “unlimited”. What is my mistake? Can you help me? Thanks!