Why won’t RealPort drivers install?

We have a Citrix environment that has six virtual machines with Connectport TS16 serial resources. RealPort drivers have been installed on the first two VMs without issue, but the third and remaining machines give errors when attempting to install. A second, identical environment is experiencing the same issue when attempting to install RealPort drivers on the third server? I have not experienced this before on previous projects. The servers are running Windows Server 2019.