Error trying to fetch more than 100 items

We are using an on premise find solution. We get the following error on our production server, but the same query and database works on our test environment. Does anybody know what could cause this?
The index is set to return 1000 items. Could this be some kind of setting on the find server itself?

System.Web.HttpUnhandledException (0x80004005): Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> EPiServer.Find.ServiceException: The remote server returned an error: (403) Forbidden.
Your account is not authorized to return more than 100 hits ---> System.Net.WebException: The remote server returned an error: (403) Forbidden.
   at System.Net.HttpWebRequest.GetResponse()
   at EPiServer.Find.Connection.JsonRequest.GetResponseStream()
   at EPiServer.Find.Api.Command.GetResponse[TResult](IJsonRequest request)
   --- End of inner exception stack trace ---
   at EPiServer.Find.Api.Command.GetResponse[TResult](IJsonRequest request)
   at EPiServer.Find.Api.SearchCommand`1.Execute()
   at EPiServer.Find.Client.Search[TResult](SearchRequestBody requestBody, Action`1 commandAction)
   at EPiServer.Find.SearchExtensions.GetProjectedResult[TResult](ISearch`1 search, SearchContext context)
   at EPiServer.Find.SearchExtensions.GetResult[TResult](ISearch`1 search)
   at EPiServer.Find.Cms.SearchRequestExtensions.GetContentResult[TContentData](ITypeSearch`1 search, Int32 cacheForSeconds, Boolean cacheForEditorsAndAdmins)