Runtime Import Normal is errior

Hi Guys! I used to IImageWrapper import local map in runtime. But when I import the normals it doesn’t work very well…I found the imported normals Compression Settings is Default(DXT1/5,BC1/3 on DX11),Texture Group is world.
The instance normal channel of a material Sampler Type is Normal… So I think the imported normal map should be compressed Normalmap(DXT5,BC5 on DX11). What should I do?