This happens when all the energies and procedures necessary for the desired outcome are aligned and ready to go. Usually, all of these factors are not in your control and maybe not even in your awareness.
Things happen when Spirit is ready, and usually not before. Your job is simply to do all that you know to do, prepare as fully as you can, and take it as a message from Spirit that something is not yet ready if your plans don’t manifest!
Don’t give up, though, because the Divine has heard you, and, when all the forces finally line up properly, Divine Timing will support your goals!