Why does texture-sampling only work at (0,0,0)?

I want to save the color of every point of one object in the RWTexture3D (UAV Resource) and transfer them to another object in its shader.

I made a test in the two shaders. Both in the fragment shader.

In first shader, I gave

RWTexture3D<float4> gUAVColor;
gUAVColor[uint3(0,0,0)] = float4(1.0f,0.0f,0.0f,1.0f);

In second shader:

Texture3D<float4> gVoxelList;
float4 output = gVoxelList.SampleLevel(Filter, uint3(0,0,0),0);

The result is correct, I got red as the result.

But when I change the code, the texture cant be sampled correctly.

In first shader, I gave

RWTexture3D<float4> gUAVColor;
gUAVColor[uint3(1,0,0)] = float4(1.0f,0.0f,0.0f,1.0f);

In second shader:

Texture3D<float4> gVoxelList;
float4 output = gVoxelList.SampleLevel(Filter, uint3(1,0,0),0);

I only changed the pos which save the red color from uint(0,0,0) to uint(1,0,0), but what I got changed to black, which means it's uncorrect.

If I use gVoxelList[uint(1,0,0)].xyz ,it works.

Does anyone have the idea where may be the problem?