Increase timeout on Angular HttpClient request [duplicate]

I am making a POST request to the backend. The stuff happening on the backend is pretty complicated, and will take a few minutes to return a response. Unfortunately, the POST request is timing out after exactly 1 minute. I need the browser to wait longer than 1 minute for a response.

Here is my original code:

bulkLookupRequest(req) {
    return this.http.post(this.bulkLookupUrl, req)
    .toPromise();
}

I have searched and searched for a solution online. I have tried:

bulkLookupRequest(req) {
    return this.http.post(this.bulkLookupUrl, req)
    .timeout(600000) // ten minutes
    .toPromise();
}

Which still timed out after exactly 1 minute.

I have also tried:

bulkLookupRequest(req) {
    return this.http.post(this.bulkLookupUrl, req, { headers: new HttpHeaders({ timeout: `${600000}` }) })
    .toPromise();
}

It still timed out after 1 minute.

Am I missing something? Could something else, like Apache settings, be interfering?