We currently have 4G of this ram and it works

https://www.skhynix.com/products/computing/view.jsp?info.ramKind=20&info.serialNo=HMT351U7BFR8A

We purchased 8G of this type

https://www.skhynix.com/products/computing/view.jsp?info.ramKind=20&info.serialNo=HMT351U6CFR8C

the only difference between them seems to be the voltage.

Please note we are not trying to mix them together, we are just trying the new memory and the server won't boot. It displays the 1/3 error (memory misconfiguration).

We also tried a few more options with ecc and none of them worked.

The processor is 

 Processor E3-1220

thank you