I have signed into the UOB TMRW app for the first time and I am trying to set up my Secure PIN. However, I have not receive any SMS OTP despite trying a few times. Why is this so?

Make sure your device is connected to the provider network. If you still don't get OTP, there is a possibility that the SMS One-Time Password (OTP) may have been sent to any previous number already registered with UOB, prior to your UOB TMRW application. Call the TMRW Contact Center: 14008 for assistance.