If you cannot get the RAM stable at XMP settings, you need to adjust VCCIO and VCCSA (System Agent) upwards. Those voltages relate to RAM overclocking. Try steps of 0.05v at a time and test for stability each step.
ASUS recommends a maximum of 1.30v for System Agent and 1.25v for VCCIO. I would assume that MSI would agree with keeping those voltages below those numbers.