Alpha transparency not working anymore

Now this is weird, I’ve always used these methods:, and they’ve worked fine… until today. This is the result that I’m getting now:

As you can see the front plane is transparent for the sky but opaque for the plane behind.

I checked all my settings and they seem to be ok… this is really frustrating.

Any help is welcome

using image alpha? if so, set base material alpha to 0. ztransp enabled. on texture, click UseAlpha.

I solved it. Ztransp helped, but I also had to tweak the settings in a different way. This was an odd and unexpected behavior.

Thanks man.