the angular rxjs timer works not like it should

In take you’re using the millisecond, you need to use the seconds here. In map you’re subtracting 1 from the milliseconds then multiply by 1000 giving you microseconds, you need to supply the correct milliseconds here.

I would do it like this:

switchMap(_ => {
  let counter = 15 * 60; // seconds
  return timer(0, 1000).pipe(
    take(counter + 1),
    // subtract the seconds that have past and turn the result into milliseconds
    map(t => (counter - t) * 1000),
    tap({
      complete: () => {
        console.log("countdown complete");
        // redirect to login page
        window.location.href = "http://IPHERE:8080/logout";
      }
    })
  );
})