I spend quite a lot of time answering Stack Overflow Blazor questions.
A very common problem for those that answerer questions is the lack of information about the render mode and Interactivity location. We can sometimes glean the options from the provided code, but we're normally left guessing.
So, if you've asked a question, and been directed here: You need to tell us about the RenderMode and Interactivity location.
Don't worry, you didn't know the consequences of the options you chose. That's Microsoft's fault for not making things much clearer.
The simplest way to find the information if you can't remember is to look at App.razor and Counter.razor.
If the 'Routes' component looks like this, you chose per Page/Component interactivity.
<Routes />
You need to dig deeper and look in Counter to find the mode.
The @rendermode Razor directive will tell you which render mode you're using.
@rendermode InteractiveAuto
If App looks looks this, you chose Global interativity. The render mode is what @rendermode is set to.
<Routes @rendermode="InteractiveServer" />
The moral of this rant is: If you want your question answered, provide enough information.