What specific problem did Das Ganu face while writing his commentary, and what was Sai Baba's initial instruction to him in Chapter 20?

According to Chapter 20, Das Ganu was writing a commentary on the Ishavasya Upanishad, titled 'Ishavasya-Bhavartha-Bodhini,' to make its meaning accessible. Although he translated it word for word, he struggled because he could not grasp its deep internal secret, and his mind found no joy in the work. When he took this doubt to Sai Baba in Shirdi, Baba did not explain the scripture himself. Instead, he enigmatically told Das Ganu that the resolution to his doubt would be provided by a maidservant at Kaka's house when he returned there.