What was the specific problem Das Ganu faced with the Ishavasya Upanishad, and how did Sai Baba propose to solve it in Chapter 20?

In Chapter 20, we learn that Das Ganu was writing a commentary on the Ishavasya Upanishad in simple language, called the 'Ishavasya-Bhavartha-Bodhini.' Although he translated it word for word, he struggled to grasp its deeper, internal secret, and his mind found no joy in the work. When he brought this doubt to Sai Baba in Shirdi, Baba gave him a surprising instruction. As recorded in Chapter 20, Baba told him that the resolution to his doubt would be provided by a maidservant at Kaka’s house upon his return.