DRAM debug LED indicates that RAM is not detected or is faulty.
Best way to test if it's the RAM, put the RAM into 2nd PC and look if the RAM works there. Best way to test if the RAM slots are working is to take 2nd set of DDR4 RAM (e.g from 2nd PC) and test each RAM slot one at a time.
If you don't have spare PC and/or spare RAM to test, take both sticks and mark on paper as stick #1 and stick #2. Now, take stick #1 and put it to 1st RAM slot, leaving 2nd slot empty. Boot up and look the MoBo debug LED. If you get DRAM lit up, shut PC down and mark results on paper. Repeat the process with all RAM slots. It looks like this:
Stick #1 in 2nd RAM slot, 1st slot empty. Boot up. Mark results on paper.
After you're done with stick #1, take stick #2 and repeat the process,
Stick #2 in 1st RAM slot, 2nd slot empty. Boot up. Mark results on paper.
Stick #2 in 2nd RAM slot, 1st slot empty. Boot up. Mark results on paper.
It's tedious thing to do but it's the only way to test RAM sticks and RAM slots.
Also, it's easier to do it when you breadboard your MoBo. Breadboarding is a technique where you take your MoBo outside of your case and sit it on top of any cardboard box.
To see how breadboarding looks, here's a pic of my Skylake build when i was breadboarding it after purchase: http://www.tomshardware.co.uk/answers/id-3232514/upgrade-seasonic-psu-full-tower-case.html#18848341
Oh, what's your RAM serial or part number? (It looks like this: CMK32GX4M4A2133C13).