https://www.babylonjs-playground.com/#JUKXQD#460
I got the playground running… but that’s all. It looks nothing like the picture. hmm.
Fixed line 31 to get PG working. Also fixed filename in line 20.
Still seeing : Error downloading MTL file: ‘weiyi2.mtl’
Is the “Sign in with Google” plane/texture… in this scene? I don’t see it/them… not even in inspector.
Viche… we need a new playground… with gridMaterial ground, and plane (with gizmos?), and dynamicTexture that says “Sign in with Google”, and nothing else… not one other thing in the PG.
No imports or mesh loads, no decal samplers, no urlsImages/pngs, ONLY EXACTLY what is in the picture.
Gotta do it. The playground you built/sent… is so full of crap… that nobody can find the issue you speak-of. 
Here is a good starter. https://www.babylonjs-playground.com/#8D6V0W
Starting with that clean playground above… now show the problem from the picture. Add the sign/plane. See instructions inside new clean playground. I think… after you add plane, texture, actionManager… to clean PG, problems will somehow disappear.
I bet so.
My wise friends here…taught me this good info. Clean and simplify the playground, and the problems often… fixes itself.
If not, paste URL to your new clean version… to this thread… and then we go to work… testing/adjusting, if needed.
Party on… we’ll talk soon, after you get your sign/plane added and clickable, and textured with dynamic texture… with “Sign in with Google” written on it. Simple. (hug)