Blazor 9: 404 error when navigation to new page

I have created a new page by creating a new componenet and adding a @page /testpage directive but when I click on a link, I get page not found.

Navigation component

<div class="topnav" id="myTopnav"><MudLink Href="/" Underline="Underline.None" Color="Color.Dark" Typo="Typo.h5" class="active">Multiple Solutions</MudLink><MudLink Href="/counter" Underline="Underline.None" Color="Color.Dark" Typo="Typo.h6">Privacy</MudLink><MudLink Href="/weather" Underline="Underline.None" Color="Color.Dark" Typo="Typo.h6">About Us</MudLink><MudLink Href="/testpage" Underline="Underline.None" Color="Color.Dark" Typo="Typo.h6">Test Us</MudLink><MudSpacer></MudSpacer><a href="javascript:void(0);" class="icon" onclick="myFunction()"><i class="fa fa-bars"></i></a>

Error I get