U2F

The U2F token is a hardware token, that communicates with the browser.

You need to set the correct appId, which in fact is the URL of your privacyIDEA installation.

AppID @if (appIdInput.errors?.['required']) { AppID is required }
The URL of your privacyIDEA installation.
This must be a valid FQDN with also a valid top level domain - otherwise you might receive a U2F Error 2 (Bad Request).
 @if (formData()['u2f.appId'] && !formData()['u2f.appId'].startsWith('https:')) {
The AppID needs to start with "https".
} @if (formData()['u2f.appId'] && formData()['u2f.appId'].endsWith('/')) {
The AppID must not end with a "/".
}