Shader transparancy not working with one half of mesh

I’ve used the following to create alpha blending.

glEnable (GL_BLEND);

And have declared the following in the alpha blending.

void main ()
outColor = color;
outColor.a *= .5;

I’ve used Alpha blend to get the transparency working however it only seems to work from one side.

Not sure what the problem is, am new to programming and shading.

Link to see the picture

fo you have backface cull enabled?