The validity of dreams as communication

قَالُوٓا۟ أَضْغَـٰثُ أَحْلَـٰمٍ ۖ وَمَا نَحْنُ بِتَأْوِيلِ ٱلْأَحْلَـٰمِ بِعَـٰلِمِينَ

They said, "[It is but] a mixture of false dreams, and we are not learned in the interpretation of dreams."