This message was posted on behalf of Intel Corporation
Thank you for posting at Wired Communities. I am sorry that we do not have information if the CT adapter is compatible with FUJITUS D3401-H1 mainboard. Our website has only compatibility information of CT desktop adapter with Intel system.
With regards to the operating system, there is Microsoft* Windows 2012 R2 built-in driver for CT desktop adapter however no Intel driver available. You may refer to the link below,
"No" Full support for CT desktop adapter which means we do not have Intel driver but only inbox driver from Microsoft. https://www.intel.com/content/www/us/en/support/network-and-i-o/ethernet-products/000005768.html
I managed to check on the Fujitsu site and found based on the datasheet of D3401-H1, Windows 2012 R2 is not listed as the supported operating system for this system on page 3
Error code refers to device driver fails, I understand you tried un-installing and re-installing the driver already. I found the Fujitsu has already an onboard NIC, have you tried disabling the onboard NIC to test?
I would suggest you to contact Fujitsu to verify on the compatibility as normally the board vendor validate the components to be installed on their system and in case they have any relevant information. Hope the above information help. Thank you.