How to Fix Black Texture on Two Sided Materials

hi guys, how do i fix black texture on two sided materials like this one:


is there any possible causes for this error?
details below

Thanks for Helping

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Try setting the normals of the two sided geometry to be up/perpendicular to the plane. This can be done in Maya/Blender etc. or through a vector in the normals node of the material. In your case, editing this in the modeling program is likely a better option.