Symptoms:
"Deleting <TENANT> tenant is not allowed as there are some product associations which still exist."
Once a tenant was associated to Aria Automation it can no longer be deleted.
This is documented within Aria Automation documentation, as:
Setting up for a multi-organization configuration
...
You cannot delete tenants in VMware Aria Automation or in VMware Aria Suite Lifecycle. If you need to add tenants to an existing multi-tenancy deployment, you can do this using VMware Aria Suite Lifecycle, but it will require downtime of three to four hours.