Have you tried both kits independently to determine that both are working ? Have you tested the memory modules individually with memtest86 ?
If so, and all is OK, you will probably need to increase your DRAM voltage to compensate for the additional load. Increase your DRAM voltage to ~1,575 and restest.
If that does not do it on its own, then you can try increasing your CPU I/O voltage one or two steps at a time until you get stability. Stay below 1,2V.
What PSU and GPU are you using?
What is your current BIOS version ? There have been numerous BIOS revisions with improved memory compatibility comments. If you do intend to flash your BIOS, use the forum flasher. It's failsafe. >>Use the MSI HQ Forum USB flasher<<