Manage subnets and IP addresses - Import/Export Error


We've recently created a new solarwinds server and wanted to migrate Subnets and IP Address data from an older solarwinds environment to the new. Under the 'Manage Subnets and IP Addresses' section on the old environment solarwinds, I have exported my discovered subnets as a zip file containing the subnet details as Excel csv files.

When I proceed to Import it to the new solarwinds environment, I select 'Import from file' and upload the zip file that I downloaded in the export earlier. When prompting to Import to continue, I am met with an error "*.zip files are only supported for 'Structure and IP Addresses' option" 

I am most definitely clicking on a zip file when I am uploading the exported documents. Would anyone know why this is happening and what I could do to resolve this?