Table near bottom lists supported RAM speeds - 1866 MHz for your CPUhttps://www.microway.com/hpc-tech-tips/intel-xeon-e5-2600-v3-haswell-processor-review/
Note: your motherboard has 8 DIMM slots not 16.
With all 16 memory slots filled with RAM, we see the DRAM frequency drops to 1866 MT/s. This is true for all motherboards when they are fully loaded with RAM. http://www.tweaktown.com/reviews/6756/crucial-ddr4-2133-drx4-rdimm-memory-review-testing-up-to-256gb/index.html
Thanks for the response Calvin, this is good to know.
I just spoke to Intel concerning the Xeon E5-2630V3, they stated the following:
"If the board supports DDR4 2133 it would work, but the processor would degrade the speed to the maximum limit of 1866"
Given this response, I am thinking that the motherboard may be the culprit here...