Why won't my RAM slots recognize my RAM?

Mac Pro unable to read RAM slots ram not detected in slot 2 Reinstall the memory module for the one not working If that doesn't work, swap the two memory modules If it still does not work, the slot ramesses riches slot game hi guys, my friend told me his laptop come with 8GB of ram 2*4GB, everything run normally but then few days ago, his Dell G3 3590 only

ramses rising slot I discovered that RAM Slot A2 does not work Both RAM Sticks work as I tested both of them in SLOT B2 So, at the moment I am only using one