If i made a new project, and choose .net 8 and connect to a MSSQL database and pick one tabel and make CRUD page.
So then i run the project and pick the new menu item nothing happens i can see in the url it have change.
Unfortunately I'm not sure what's causing this error at your end. If you have Radzen Blazor Studio subscription you can send us an application demonstrating the problem at info@radzen.com.