Motherboard won't accept 2nd ram

[plee21]

I had just finished building my pic and I turned on the pic and it was running fine. It wasn't until later I noticed one of my ram sticks not properly in and so I turned everything off and plugged in the ram stick. But then my computer starts but my monitor doesn't turn on and my computer then restarts. They are both the same ram stick I checked. They both work individually I've tested it. Same model too.
I'm using a gigabyte z170xp and ram is a ddr4 g skill. I've placed the ram in the 2nd and 4th slot the 4th spot does not work

 

[crispykiller96]

Stupid question have you put them both in the correct slots usually coloured also even more serious is the CPU ok no bent pins certain pins control the RAM Slots so even the slightest no contact can cause issues

 

[plee21]

Stupid question have you put them both in the correct slots usually coloured also even more serious is the CPU ok no bent pins certain pins control the RAM Slots so even the slightest no contact can cause issues

Yes they were in the correct slot 2 grey slots 2nd and 4th

 

[smorizio]

on the mb use guild from the bottom ram slots are 1/3/2/4 bank a are ram slots 2/4. b back are the two lower slots per the mb user guild. also make sure the mb has the newest f6 bios on it.