Glide not caching images

For some reason glide is not caching the images. After loading images, I restart the app but Glide will download the image again.

The server does return a unique url each time but I am providing a signature that does not change. Glide version 4.9

Glide.with(context)
     .asBitmap()
     .load(url)
     .diskCacheStrategy(DiskCacheStrategy.RESOURCE)
     .signature(ObjectKey(url.substringBefore(delimiter = "?")))
     .into(imageView)