In the /var/log/vmware/vcf/domainmanager/domainmanager.log you see similar messages as below:
ERROR [ c.v.v.c.f.p.a.impl.ConfigureNfsDatastoreAction] Execute ConfigureNfsDatastoreAction failed during creation of datastore nfs-datastore with the exception of {}
com.vmware.vim.binding.vim.fault.AlreadyExists: The specified key, name, or identifier '/vmfs/volumes/c299ac45-0bc1248d' already exists