I was trying to use search endpoint("https://api.spotify.com/v1/search"), but response return empty items. As ex. of response(changed link-title, because system doesn't allow):

"tracks": {
    "": "https://api.spotify.com/v1/search?query=remaster%2520track%3ADoxy%2Bartist%3AMiles%2520Davis&type=track&market=ES&locale=en-US%2Cru-RU%3Bq%3D0.8%2Cru%3Bq%3D0.5%2Cen%3Bq%3D0.3&offset=5&limit=10",
    "items": [],
    "limit": 10,
    "next": null,
    "offset": 5,
    "previous": "https://api.spotify.com/v1/search?query=remaster%2520track%3ADoxy%2Bartist%3AMiles%2520Davis&type=track&market=ES&locale=en-US%2Cru-RU%3Bq%3D0.8%2Cru%3Bq%3D0.5%2Cen%3Bq%3D0.3&offset=0&limit=10",
    "total": 0
  }

 Request has been filled with sample data. Problems started from 9:00 PM(UTC +2).

Maybe there some restrictions? But the other requests passed and response is correct.