Installing .Net Framework 4.8
.Net Framework 4.8 Runtime must be installed on the server that is hosting AuctionWorx 3.5.
Windows Server 2022 comes with .Net Framework 4.8 pre-installed but, Windows versions older than 2022 will require a manual installation.
Below is a link to download the .Net Framework 4.8 Runtime installer:
https://dotnet.microsoft.com/en-us/download/dotnet-framework/net48
Note: After installation the server will need to be rebooted to take effect.