| If the exchange server does not provide OWA services, this check is Not Applicable. |
If the exchange server does not provide external OWA services, https does not need to be assigned to external URL, it may be blank.
Open the Exchange Management Shell and enter the following command:
Get-OWAVirtualDirectory | Select Name, Identity, ExternalUrl, InternalUrl
If the value returned is not both ExternalUrl and InternalUrl and these are not set to https://, this is a finding.