PC stuck in boot loop if i use my RAM in the first slot or in dual channel

[mikusgraudins6]

My motherboard has 2 ram slots. If i use the second slot, everything works fine, but if i use the first one or i have my ram in dual channel, pc is stuck in a boot loop.

Are there any other possibilities than a dead RAM slot?

 

[gdmaclew]

System specs please.(at least the motherboard make and model number).
How many RAM sticks do you have?

 

[mikusgraudins6]

System specs please.(at least the motherboard make and model number).
How many RAM sticks do you have?

Mobo - Asrock H110m-HDV
RAM - 2x 8Gb DDR4 (one is 2400 17CL and the other one 2133 15CL)
I heard that different clock speeds and CL numbers can fit together.
And if its the motherboards slot fault, shouldnt it be that it just cant detect the ram and i am able to boot?

 

[mikusgraudins6]

There was some dust in the CPU socked cobering 3 pins.
Cleaned it and now everything works fine