If you see this error message when updating your mobile number, it means the mobile number is currently registered to another Singpass account. For security reasons, each mobile number can be linked to only one Singpass account at any given time.

How to resolve this issue

If this mobile number belongs to you and you would like to use it for your Singpass account, please contact our Singpass Helpdesk. Our team will assist you with the necessary verification steps and guide you to update your mobile number securely.