Using the Backup and Replication 126.96.36.19966 Update 4b iso, the Veeam installer will fail after at the "Provide License" dialogue with the following error:
"The user don't trust the certificate or the admin policy has disabled user trust. Error: 0x80096005"
After clicking OK on this pop-up, you will see another that says "The provided license is not valid".
This is a false error in this case, as the license was just recently purchased.
The Veeam install wizard allows you to bypass this licensing dialogue and install a license key later. Choose this option by clicking Next at the "Provide License" dialogue.
Complete the installation of Veeam using your desired configuration settings.
Once the install has completed, reboot if the machine on which you have installed Veeam.
Once rebooted, log in to the OS on which you are hosting Veeam and open the application by double clicking the green "Veeam Backup & Replication Console" shortcut on the desktop.
Your server should allow you to log in with the default settings. Otherwise, specify the IP address of your host and click "Connect".
Once the application opens up, click on the Menu icon in the top left corner and select License:
On the "LICENSE INFORMATION" dialogue, click "Install License".
Browse to the location of your license file (should be named "veeam_backup_perpetual_*_*.lic") and click OK.
Your new license will be applied to the application.