There are several possible reasons why this might've happened:
1) Your mobile number has been registered before with Signature Market
2) Your mobile number might have been entered incorrectly.
3) Your mobile network connection is unstable, try to restart your phone and move to a spacious location.
4) Your mobile network operator might be taking a longer time than usual to send the TAC code to you, try clicking on the "Request again" button and wait for a while longer
5) Is the number 66688/68886 in your SPAM list? Kindly unblock it for the TAC code successfully send to your mobile.
If this issue persists, please take a screenshot of the error message (if any) and drop us a message along with your contact number + telco and email address at email@example.com.
We also suggest customers to try by using any alternative number to get the TAC code.