Can you explain the story of Das Ganu's struggle with the Ishavasya Upanishad as detailed in Chapter 20?

Chapter 20 recounts the story of Das Ganu, who undertook the task of creating a commentary on the Ishavasya Upanishad, called the 'Ishavasya-Bhavartha-Bodhini,' to make its meaning accessible to those who did not know Sanskrit. As described in the chapter, despite translating the text word for word, Das Ganu felt he could not grasp the 'internal secret,' which left his mind without joy. Faced with a specific doubt, he traveled to Shirdi to seek guidance from Sai Baba. In a mysterious turn, Baba told him that his doubt would be resolved by a simple maidservant at Kaka’s house upon his return, a story which sets up the next part of the narrative and highlights the theme of Guru's grace that is central to Chapter 20.