PowerCLI-Import OVF | The OVF descriptor is not available

I always encounter “The OVF descriptor is not available” when using the Web client to import OVF

If i use the PowerCLI below to import OVF with the same OVF file, it will be always successfully

#Login to vCenter / vSphere Host
Connect-VIServer -Server -User administrator@vsphere.local -Password P@ssw0rd

#Map Network Drive to T:
$net = new-object -ComObject WScript.Network
$net.MapNetworkDrive("T:", "\\\f$", $false, "MYMDT\administrator", "Azur3.t3st123@")

$ovf="T:\Nimble Storage\NimOS-"
Import-VApp -Name NimOS1 -Datastore SSD -VMHost "" -Source $ovf -DiskStorageFormat Thin 

Get-VM -Name NimOS1 | Start-VM