Flickering?

Hello,
did anyone know why I get this effect? In close range it looks good but in far range it get unclear and starts flickering.
This mesh is made out of some unreal cube that I merge together. The Material is just a color multiplier with GlowIntensity and put in Emmisive Colors.
Shader model is default lit.
How can I get rid of this effect?

I already search for a solution but I can not find any clue :frowning: