Issues Building X10SLM-F based system

I recently purchased the parts to build a new unRAID server based on this guide. I purchased the
X10SLM-F board
16 GB 10600E “ECC UDIMM” DDR3 Server Workstation
and an SR150 Intel Xeon E3-1280 v3.
The system also has a dual NIC card and a card to attach my DAS.
When I boot, it does not post, it just outputs error code 55 which I understand means no RAM, when I swap the RAM for known good ECC RAM pulled from a working Dell R410 is outputs error code 15 which I understand means non-ecc RAM.
Any ideas what I’m doing wrong here? I’d like to not have a $600 paperweight in my office.