Remaining Storage Can't Be Correct

Nextcloud version 20.0.5
Ubuntu 18.04.5 LTS Server
Apache 2.2.46
PHP 7.3.26

Nextcloud 20 is installed on a Ubuntu Server VM with a hard disk size of 50GB. Nextcloud Admin System page says total storage is 45GB and only 2GB remain available. I’ve used 2.8GB as Admin and when I scroll through the users, they have used no more than 500 MB between all of them. I should have about 40GB of storage remaining, Nextcloud says 2GB.

What might cause such a large discrepancy? Any ideas of how to fix? Thanks

Does anyone have an idea why Nextcloud appears to be incorrectly reporting available storage?