What challenge did Das Ganu face while working on the Ishavasya Upanishad, and what was Sai Baba's initial advice?

According to Chapter 20, the devotee Das Ganu undertook the task of creating a commentary on the Ishavasya Upanishad in simple language, called the 'Ishavasya-Bhavartha-Bodhini.' Although he translated the text word for word, he struggled to grasp its deep, internal secret, and his mind found no joy in the work. Feeling stuck, he took his doubt to Sai Baba in Shirdi. Baba's advice was cryptic and insightful; he told Das Ganu that the resolution to his doubt would be provided by a maidservant at Kaka’s house upon his return.