Unable to import texture with .dae file

I have made a first model successfully with textures.

But now I’m working 2nd model doing the same way I did the first one. This time it did not do it. The textures are there in blender and it does show but it does not show on Workshop tool on TU. I have no idea why it didn’t do it on the 2nd model when the 1st did.

I think TU only supports .jpg and .png files as materials.

On https://www.towerunite.com/sdk/troubleshooting, the section about textures should help.

I have been using jpg files. I also notice something else. I can’t able use solid color like red. I made another object using same texture from the first image. Its a success. But it still say missing texture in compiler log. Its fine in the preview.But when I try to use a solid color like red, it just isn’t working with just a solid color. But solid color of silver went ok with no issues. I’m still looking for tutorials about it. I’m thinking maybe red shouldn’t be completely red. Probably adding tiny bit of other colors may help but I’m not that will work though.