Issues implementing error handling for Angular POST request

For some reason my Angular code can't correctly handle error conditionals for a POST request.

For context, the relevant call is in a component.ts:

this.crazyService.addSomething(stringifiedContent).subscribe(
data => {
          console.log(data);
          this.showSuccess();
          setTimeout(() => {
            this.dashboardRedirect();
          }, 2750);
        }
)

In the 'crazyService' the code is

addSomething(something: any): Observable<any> {
    const headers = { 'content-type': 'application/json' };
    const body = JSON.stringify(something);
    return this.http
      .post<any>(this.relevantUri, body, { headers, observe: 'response' })
      .pipe(
        catchError(err => {
          console.error(err);
          throw err;
        })
      );
  } 

The POST request works fine, however for some reason the console.log(data), this.showSuccess() and timeOut don't work here.

Whereas when I do this in my component:

this.crazyService.addSomething(stringifiedContent).subscribe( hello => {
console.log(hello);}
, data => {
          console.log(data);
          this.showSuccess();
          setTimeout(() => {
            this.dashboardRedirect();
          }, 2750);
        }
)

It enters the data part and does the things I want whereas in the previous example it doesn't seem to enter that block.

Why is this the case? And how can I fix this so that I can have a case for when the POST request is successful, and another for when there is an error?