Yes that's it and as @Lost_N_BIOS also noted, i did saw on the bottom of the socket some other not so conclusive area that may be affected.
Use a nice lamp and a magnifying glass to do an exhaustive search on the socket for debris, clean it as was already instructed to u by @Lost_N_BIOS post
or a more uncomfortable approach can be done with a needle or tweezers carefully clean the debris and always try to cover it whenever the socket is not populated.

Attached are screenshots of the bios out there you see something that by setting it up can make all 4 ram's work.

The bios looks ok but I would recommend you to unplug the pc, remove the CMOS battery for a couple of minutes for it to reset everything. Reflash the bios using intel fpt instead of MSI M-flash. If it still doesn't work, you may have an hardware problem (bad cpu, bad socket, bad motherboard)
Because you bought the motherboard used and it came with a M.2 to pci-express adapter, I guess your motherboard was used for mining cryptocurrency and that kind of hardware has a lot of stress on it.

Looking at bios used bank slots, it is advised to be as 1rst channel populated the A2-B2 (U have A1-B2), use the motherboard manual.
Now looking ur modules...running 2 very different modules specs, not even an equal frequency...2400 and 2133, very bad choice, its always recommended a similar pair of modules using dual channel memory banks.
Now if the 2 other 4Gb modules that u have are also a complicated mix of specs...putting all them 4 together...then yes, i do believe that u can have here a bad situation on ur hands.
U can mix modules from manufacturers but in modern dual channels motherboards, the modules have to be the same size and frequency, preferentially from the same manufacturer if u want to achieve a stable system.
As always...this is only my perspective view of ur situation, no statements or miracles here. Good luck.

Thanks to everyone, it seems that it is impossible to work with the 4 ram modules, it is not like my old asus b250f that worked with any ram module. You can close the subject. I thank again all the people who helped me.

Best regards.

Hello, sorry for the delay. I am thinking of buying an i3-9100F, will it be better than the processor I currently have an i7-7700 ?? And it goes to the motherboard theme because I would modding it with the Easy automated Mod tool for Coffee Lake bios. I know that an i3-10100 beats my i7-7700 but it is not within my capabilities because I have no money to buy the processor and the new motherboard. But it is enough for me to buy an i3-9100f. On the cpu comparisons page UserBenchmark shows the i3 better than my i7 but I wanted to ask you guys since I don't trust those comparisons pages very much.
Thank you very much in advance.
Best regards.

Hello, I disassembled the pc and cleaned the cpu socket of the motherboard, then I assembled the pc but it still doesn't work with the 4 ram modules, it only works with two. It will be some restriction on the part of msi because, as I commented before, in my old motherboard b250f I ran with all different modules. Or maybe this msi board that I bought second hand came bad, I don't know. I await your suggestions.
Thank you very much in advance.
Best regards.

I tried everything already, but well, this particular board only works with two ram modules. Well, thank you all very much.
Best regards.

Hi, I removed the msi motherboard, now I'm with an asrock, I took new pictures of the msi board with the problem of the initial post.
If you need to see other photos of the motherboard or more photos of the cpu socket I will gladly take more photos.
I look forward to your help.
Thank you very much in advance.
Best regards.

At least the top one is not in place, below its STILL not clean...and cannot tel if there is damage

https://app.box.com/s/gcsq3gldohtmgksdok9rei60jtrk6h7p

Thanks.