The API will default to deny access unless it finds proof that your api key has acces to the resource. Remember to add the parameter "?orgId=<your_id>" when searching and always use your api key in the header named 'x-finn-apikey'.
Some of our clients have a wast amount of adverts. To be able to serve our client as quickly as possible we paginate the results returned by the search. We also include pagination links in the top of the XML. The default rowsize for a result page is 30, but this can be increased with the '?rows=<number_of_rows>' parameter. Maximum size is 1000.
Usually this is because you did not follow links provided in the response or headers, but instead constructed URLs based on the false assumption that URLs for every ad will be similar. In fact, advert URLs may differ and even change. The only way to confidently get a correct URL is to either follow a link or apply one of the URL templates described in the Service Document.