Time of Geula Not Revealed from Heaven
The last question posed by the author of She'elot Utshuvot Min Hashamayim was when the Geula would come. According to the book we have in front of us, no answer was given (as opposed to the other 69 questions).
However, in the Lev Malchus newsletter (p. 3), there is a different version. Apparently, the following answer was given:
מי שאל - who would ask such a question? אלצפן - Hashem has hidden the answer. סתרי - This cannot be revealed, but must be covered and hidden.