Guys!! I got all six working. What did it was actually the fix in https://forums.geforce.com/default/topic/470858/code-12/ that someone suggested to you Yoledo, I suggest you try it again if you havent done what i shortly describe:

More exactly going to the 'memory' tab,  and inactivating hd audio controllers under pci root port #1 or in your specific case the pci-e port that aint working.

No restart no nothing required, exclamation mark just went away.

Good luck!