You need to protect your MitID authenticator with the same carefulness and eagerness as you protect your house keys – that way you protect your identity from theft.
Should you lose your authenticator, you must block it immediately. You can block it yourself or you can contact MitID Support and have them do it for you.
How to block a MitID authenticator
Contact MitID Support
I have lost my smartphone with the MitID app installed
It is important that you block both the MitID app and smartphone’s SIM card.
When you install a new MitID app on a new smartphone, there is a difference between a SIM card with new phone number or a SIM card with the old number. If you get a new smartphone with a new number, you need to confirm the new number, before you can use the MitID app on your new smartphone.