No results in Content Search API

Hello, I have a problem with usage of the Content Search API --

I have installed Content Search API by following instruction at the Episerver World. However, the API yields no results:

{"totalMatching": 0,"results": null}

The configuration of Episerver Find seems to be proper, i.e.:

• There are Document Types listed in Overview on the Find page.
• There are results if I'm using Episerver.Find.Client: Client.CreateFromConfig().Search<FindDocument>().GetResult(); // yields proper results.

Now, I tried to use the API in following ways. All yields no results and there's no error in the logs.

Method 1: By using Swagger UI.

Method 2: By using Visual Studio Code Rest API Client.:

### Search
GET {{baseUrl}}/{{v2}}/search/content
?languages=sv
&query=*
Accept: 'application/json'
Accept-Language: *
Authorization: Bearer {{accessToken}}

Method 3: By using the code directly:

var searchResponse = _contentApiSearchProvider.Search(new SearchRequest { Query = "*", }, new List<string> {"sv"});
var contentApiModels = searchResponse.Results?.ToList(); // is null

Using following package versions:

<package id="EPiServer.CMS" version="11.15.0" targetFramework="net48" />
<package id="EPiServer.ContentDeliveryApi.Cms" version="2.10.0" targetFramework="net48" />
<package id="EPiServer.ContentDeliveryApi.Commerce" version="2.10.0" targetFramework="net48" />
<package id="EPiServer.ContentDeliveryApi.Core" version="2.10.0" targetFramework="net48" />
<package id="EPiServer.ContentDeliveryApi.Search" version="2.10.0" targetFramework="net48" />
<package id="EPiServer.ContentDeliveryApi.Search.Commerce" version="2.10.0" targetFramework="net48" />
<package id="EPiServer.Find" version="13.2.6" targetFramework="net48" />
<package id="EPiServer.Find.Cms" version="13.2.6" targetFramework="net48" />
<package id="EPiServer.Find.Commerce" version="11.1.2" targetFramework="net48" />
<package id="EPiServer.Find.Framework" version="13.2.6" targetFramework="net48" />

I tried different variations of the query and request configuration, but none of these solutions yields proper results.

Do you know what might be the cause of that?