After Lord Yama Shangguan Qingtian healed Underworld Consort Han Zixiong's injuries, he immediately contacted the Heavenly Emperor Yu Siang, who had just descended to the Mortal World. When Mr. Jade Emperor received the call from his subordinate Shangguan Qingtian, he had just landed above Demon City.
As for why it took him so long to successfully land, it's a rather sad story. Yu Siang thought he would be able to pinpoint Demon City's location in a flash and then reach his destination in another flash.
Unexpectedly, there was a mana barrier above Demon City that was extremely strong, blocking the invasion of outsider creatures, especially aimed at stowaways like him. Fortunately, Heavenly Emperor Yu Siang's mana was still powerful, and his IQ was still intact. The behind-the-scenes big shot of the Eastern Celestial Court had put in herculean efforts and finally managed to crack the barrier.
