All of the memroy become question mark all of a sudden

I am very new to Nsight and this forum, and I am working on my thesis which involves CUDA programming, and I deeply appreciate any form of help, because I realy got stuck hear.

Unfortunately, my kernel function crashes for global memory access failure, and I realy have no explanation for it. I installed Nsight to understand why, and I realized that the cause of the error is not out-of-scope indexing of array, but it is because all of the array elements, which are located in the global memory, suddenly become question marks (in the memory window of Nsight), therefore when I access them it gives me an error.

It is important to note that this happens when I add two extra for loops to my code. Before that my code works perfectly well. So, I increased the number of the for loops in my kernel from 2 to 4 and got this error.

So, my question is: why an array, which is a big chunck of global memory, with all of its elements all of a sudden become question mark in middle of kernel execution? Just to say this that this happens to all of my buffers on global memory, not just one buffer.

I attached the image of the nsight memory table