An activation can fail for various reasons. First try the following steps:

– Check that you’ve entered the complete 13-digit number of your SIM card correctly. It’s on the back of the plastic SIM holder.

– Have you recently requested a number transfer? Then your SIM card can only be activated once the transfer is complete. Check the status in our app or My account at https://wsc.undo.be/?lang=en — a green frame around your number means your number is active.

– If it still doesn’t work, contact us with your SIM card number (13 digits). We’ll check from our system what’s going wrong.

Do you have an eSIM instead of a physical SIM card? Then check our FAQ “My eSIM is not working”.