WPF App with Identifier First Returns 'Object doesn't support property or method initCustomEvent' error

Problem statement

When enabling Identifier First in the Auth0 dashboard and going through a login event with a WPF application, an error is returned if a user attempts to edit the email address they initially entered. The error message pop-up is:

Object doesn’t support property or method ‘initCustomEvent’

What updates need to be made to the WPF application to avoid this error?


The error is likely occurring due to running the Auth0 WPF SDK as an Administrator, which uses Microsoft Internet Explorer as the default browser. This browser is quite old and missing a number of enhancements necessary for newer Auth0 features (such as the Identifier First flow).

This is a known limitation with the WebView components provided by Microsoft.


To resolve this issue, please refer to this knowledge solution HOW TO: Use the Auth0 oidcClient.WinForms SDK with Edge Chromium / WebView2 which provides a workaround to use Edge Chromium browser instead of Internet Explorer.