The MobileID app is an OTP app as well as an OOBA app. If a token is to be used for OOBA, then while the token is being installed, it must also be registered for OOBA operation.
There are several ways of installing a MobileID token. However, in order to register a token for OOBA, you must install the token using QR code or download link.
In the process of installing a token, you will be asked if they want to register the token for OOBA. You must press the "REGISTER" button