Error on Sneak Peek

Hello!
I’ve been installing Verge3D and trying to test a scene through Sneak Peek but this error appears:

Traceback (most recent call last):
File “/Users/J.BETBE/Documents/Blender/verge3d/addons/verge3d/custom_ui.py”, line 352, in execute
filepath=join(prev_dir, “sneak_peek.gltf”), export_quick = True)
File “/Applications/Blender/blender.app/Contents/Resources/2.79/scripts/modules/bpy/ops.py”, line 189, in __call__
ret = op_call(self.idname_py(), None, kw)
RuntimeError: Error: Traceback (most recent call last):
File “/Users/J.BETBE/Documents/Blender/verge3d/addons/verge3d/__init__.py”, line 220, in execute
return gltf2_export.save(self, context, export_settings)
File “/Users/J.BETBE/Documents/Blender/verge3d/addons/verge3d/gltf2_export.py”, line 82, in save
generate_glTF(operator, context, export_settings, glTF)
File “/Users/J.BETBE/Documents/Blender/verge3d/addons/verge3d/gltf2_generate.py”, line 2949, in generate_glTF
generate_node_graphs(operator, context, export_settings, glTF)
File “/Users/J.BETBE/Documents/Blender/verge3d/addons/verge3d/gltf2_generate.py”, line 2362, in generate_node_graphs
graph = extract_node_graph(bl_node_group, export_settings, glTF)
File “/Users/J.BETBE/Documents/Blender/verge3d/addons/verge3d/gltf2_extract.py”, line 1362, in extract_node_graph
node[‘outputs’].append(bl_output.default_value)
AttributeError: ‘NodeSocketShader’ object has no attribute ‘default_value’

location: /Applications/Blender/blender.app/Contents/Resources/2.79/scripts/modules/bpy/ops.py:189