I've lost count of memory clocking issues. As such here's the drill.

1. Update to the latest BIOS.
2. Try again.
3. Try XMP.
4. Post the issue in the motherboard maker's motherboard support forum.
5. If still non-functional, RMA that board and try a Ryzen board they use at PCMR.
Link: https://www.reddit.com/r/PCMasterRace/wiki/builds