In this case, the client machine can:
- Reach the OIP webserver's page
- Reach the IIOP port (2809) and HTTP port (80) using telnet
- OfficeSuite still fails and says it cannot connect to the server
After much struggling, it was noticed that the host name on the server itself resolves to an IPv6 Link-Local address. Removing IPv6 support on the interface and a reboot of the OIP server resulted in a working connection.
Addendum: Sometimes it is not so simple to disable IPv6. This link helped: https://tweaks.com/windows/40099/how-to-properly-disable-ipv6/
