This could be caused by:
1) You may have an incorrect mobile phone number registered in Board.Vision. You can check with your administrator whether your mobile number is correctly registered in Board.Vision.
2) A poor cell phone reception that may stall your OTP SMS. You can generate your OTP by using an Authy App.
For more information on how to download and install Authy, you can refer to the link below:
If you still encounter the issue, please contact us at +65 6909 7100 or firstname.lastname@example.org.