config.kit.adapter should be an object with an “adapt” method

I want to use the @sveltejs/adapter-static in my Svelte Kit app (want to turn it into an SPA).
I installed the adapter static with npm i @sveltejs/adapter-static.

The code in the svelte.config.cjs looks like this

kit: {
    // By default, `npm run build` will create a standard Node app.
    // You can create optimized builds for different platforms by
    // specifying a different adapter
    adapter: adapter({
        fallback: 'app.html'
    }),

When I start my app with npm run dev I get the following error:
config.kit.adapter should be an object with an "adapt" method

How can I fix this?