Thank you for your update. I successfully resolved the issue. Indeed it has nothing to do with the network.
Out of curiosity, and I might be mistaken, I noticed that SIMBA's network filtration might not be very robust. Several times at a coffee shop in Bukit Batok, I experienced long delays in loading Lazada and Shopee pages. Similarly, at a residence in West Toa Payoh, loading the POSB App, especially its investment section, only occurred when I moved to an open space. Lastly, I believe there might be a network issue in basement carparks, I only received the road directory message I sent from my mobile phone, after leaving the basement carpark. Anyway, I am just sharing my observations as a new user. Thanks.