I had something similar but not quite the same. Just built a new PC with this Ranger motherboard and have the same Corsair Vengeance 2x4GB RAM as the user above (CMY8GX3M2A2133C11R).
The QR code on the motherboard would stop at '55' - looking at the motherboard manual, that indicates the DIMMs aren't present. I reseated several times and had the same problem each time. I decided to try one stick at a time, and they both work individually (note you have to use the A1 or B1 slot for single RAM sticks, the red and black slot 2s are only for dual sticks).
So knowing that the RAM itself was just fine, I did some googling and could find three or four mentions in the ASUS forum archives that suggested the problem can be related to the pressure exerted by the CPU cooler (either too much pressure, too little pressure, or uneven pressure). So I reseated the CPU cooler several times, and on one occasion, was actually able to get to the BIOS. But not consistently.
The same aforementioned forum posts also indicated the problem could also be caused by bent pins in the CPU socket. When I took a magnifying glass to the socket (I really couldn't see anything wrong without it) I could see what looked like a misaligned pin. It took a while for me to figure out how the pins are actually laid out, but once I understood what I was looking at, even magnified, I was able to gently push the pin back into alignment.
Putting it all back together, the system booted no problem at all.
This may or may not shed some light on what you're seeing here, and whilst I did a search using these forums' search function, searching for '55' does not return any results. It's a real pity because the QR code from the motherboard is pretty much the information I needed to find some clues as to what my problem was.
So you should try googling your QR code, because the search function here appears a little lacking. HTH.