fitting problem

Hello everyone I have a complete mind block and trying to explain to a friend what this AG adapter is and could use some clarification. My friend is planning on doing a water loop and came across a inline temp probe with a AG adapter...

I’ve built this computer myself a couple years ago. But I’ve run into a problem. When upgrading from 2x4 to 4x4 (using all my ram slots now) the computer power cycles constantly without ever allowing to go to BIOS. Stays on for 10 seconds then off for 10 seconds. Now here’s a concerning thing...