Only 2d assets work, but not 3d assets, just like in the screenshots.
When I edit the 3d one, nothing shows up in the screen.
Is there anybody who knows how to fix this? 
Did you enable the fluid simulation plugin?
You mean Niagara Fluids Beta plugin?
Yes, of course~
Having the same problem here. Basic Niagara emitters and the 2D Niagara Fluid emitters seem to work but the 3D Niagara Fluid template systems are blank.
Did you ever find a resolution?
I have the same issue. I’m glad that I’m not the only one.
我有同样的问题。我很高兴我不是唯一一个。
Did anyone post a solution yet?
I got the same issue and fixed it.
Open up the Niagara System, click the 3 dots besides Compile and hit Full Rebuild. Save it and it worked for me.
Thank you, that solved it for me. 
i’m on M1 as well, still nothing but i saw someone else who has m1 and theres seems to work but mine for some reason doesn’t.
Nothing Still works, even with fluid one. I updated to 5.2 but still no change.
Sometimes making the size of the pool to a cube will make it visible and slowly adjusting the size will let you know what it can’t do. This niagara pool system is pretty ■■■■ put hey ho
For 3D fluid simulation, I found out that my problem was that in the Niagara system editor, down on the timeline, I had start set to time other than 0. Setting it to 0 made the water appear.
However, I haven’t been able to get the 3D gas simulations to appear. Full recompile made no difference. I can confirm that 2D simulations work as expected.
In case anyone else has this problem: I found that deleting my Sky Dome fixed the problem.
It’s already 4 years, did anyone found the solution yet?