❔ MAUI blazor windows handle URI

Hey so, I've been trying to get MAUI blazor to run as a single instance to handle custom URIs, with no success, I tried following this tutorial: https://blogs.windows.com/windowsdeveloper/2022/01/28/making-the-app-single-instanced-part-3/, but I get an error saying the key is null or something... I really need help on this one