Transparency in texture become black when exported GLTF

Hello everyone!

I have problem in exporting file.

This is the project (downloaded from Sketchfab)

After I exported it as .glb or .gltf, the transparency of the texture become all black!

How can I keep the transparency of the texture? Thank you.

Were you able to solve this?

It looks like a bug, so it might be worth filing something on https://github.com/KhronosGroup/glTF-Blender-IO. If you can share the .blend file, that would help too. If not, does the file have an alpha texture? Or a single base color texture that includes color and alpha?