T340 Memory Error w/ UDIMMs

I have a T340 with 64gb 2666 UDIMM (4x16GB) with E-2174G and system shows "Memory Error; an error was detected during memory initialization. Verify DIMMs are properly seated and that they are installed in correct slots."

I was able to get the unit to POST and updated firmware/BIOS by swapping the processor with a Celeron G4930 but when i reinstall the E-2174G the memory error comes back and unit will not POST. I've swapped DIMM slots over and over and drained flea power. I also tried other UDIMMs but the error remains. any insight?