Question Pc won’t post with anymore than 1 stick of ram. Help!

Jun 2, 2021
Pc was working fine yesterday. I built it about 2 years ago. When I went to boot it up today I keep getting error code 0d. Pc will not post with anymore than 1 stick of ram. I have checked all 4 sticks and all work on their own so the problem isn’t the ram itself. Hoping someone can help me as I’m not very advanced when it comes to PCs.
Ram is HyperX 8gb
Motherboard is Asus Strix x399
Do the 4 Ram modules you are using come from a single kit or are you trying to mix kits?
If you are trying to add more RAM to the Hyperx 8GB module then you may have a mismatch.
Did you test all modules in all different RAM slots?