The problem of replacing RAM in imac 27 2019, who will advise what?

Question

RAM

I decided to change the RAM by buying 4 modules of 8GB each (RAM 8 GB 1 pc. HyperX HX426S15IB2/8)
When 2 modules are connected, everything works well.
When I run it with 3 or 4 modules, it starts with a black screen, which does not go into boot mode or anything after an hour or two.
Perhaps someone has come across this issue.

Answer 1

For iMac 27 2019, DDR4 2666Mhz CL19 memory is required - these are the characteristics of the standard installed Apple memory. And you have CL15