I'm sure at 99% that your issue are not related with FQDN path. You need to know that WPP is not responsible for the path where Wsus store package. The path you can see on the 'Informations' tab is create by WPP only to be displayed. It is not used for download/installation by Workstations.
Try this :
Try this :
- From the screenshot, click on the id (8f8a8ce-...). This will open a new window.
- Open the folder where you can find the exe or the msi you have publish
- Copy it on a Workstation that have the problem
- Right click on the file and choose 'Properties'
- Open "Signature" tab and see if the certificate is trusted.