Can you explain the story of Das Ganu's attempt to write a commentary on the Ishavasya Upanishad from Chapter 20?

Chapter 20 recounts the story of Das Ganu, who began composing a commentary titled "Ishavasya-Bhavartha-Bodhini." His intention was to explain the meaning of the Ishavasya Upanishad in simple language for those who didn't know Sanskrit. However, he found that while he could translate the words, he couldn't grasp the deep, internal secret of the scripture, and his mind found no joy in the work. When a particular doubt arose, he took it to Sai Baba in Shirdi. Baba cryptically told him that the doubt would be resolved by a maidservant at Kaka's house when he returned.