This suggestion of adding market query parameter fixed problem in my case.
Previous non-working query
REQUEST
https://api.spotify.com/v1/shows/2yB9jTRog4XGCKG5bpNZUA
RESPONSE
{
"error": {
"status": 404,
"message": "non existing id"
}
}
Working query
REQUEST
GET https://api.spotify.com/v1/shows/2yB9jTRog4XGCKG5bpNZUA?market=FI
RESPONSE
{
"available_markets": [
],
"copyrights": [],
"description": "The AIAS Game Maker’s Notebook is a podcast featuring a series of in-depth, one-on-one conversations between game makers. Each episode is hosted by a fellow game maker and provides a thoughtful, intimate perspective on the business and craft of interactive entertainment that will explore the tenants of D.I.C.E.; Design, Innovate, Communicate, and Entertain.",
"episodes": {
"href": "https://api.spotify.com/v1/shows/2yB9jTRog4XGCKG5bpNZUA/episodes?offset=0&limit=50&market=FI",
"items": [
{
"audio_preview_url": "https://p.scdn.co/mp3-preview/b6b67e9c7661eee91417af60ba55c0320f6d68a0",
"description": "Siobhan Reddy (LittleBigPlanet) sits down with Ted to talk about the upcoming game Dreams, the importance of community support, user-generated content, and the \"glitter and doom\" that comes with being a game developer. Reddy is the co-founder and studio director of Media Molecule. The studio is best known for their title LittleBigPlanet. For news and info on the AIAS, follow us on Twitter @Official_AIAS, Facebook or visit us at interactive.org. Email us at *snip*.",
"duration_ms": 3514944,
"explicit": false,
"external_urls": {
"spotify": "https://open.spotify.com/episode/36SMkU9lPQUq85NQQBWET7"
},
"href": "https://api.spotify.com/v1/episodes/36SMkU9lPQUq85NQQBWET7",
"id": "36SMkU9lPQUq85NQQBWET7",
"images": [
{
"height": 640,
"url": "https://i.scdn.co/image/50a1d65377814fea4446a51f05c2a29d5231dbbe",
"width": 640
},
{
"height": 300,
"url": "https://i.scdn.co/image/e599b62b786ed24e455ecad8a454832ba03886b1",
"width": 300
},
{
"height": 64,
"url": "https://i.scdn.co/image/529732d4cc66f8bfd164169d7200eb17b08242dc",
"width": 64
}
],
"is_externally_hosted": false,
"is_playable": true,
"language": "en",
"languages": [
"en"
],
"name": "Media Molecule's Siobhan Reddy",
"release_date": "2018-07-03",
"release_date_precision": "day",
"type": "episode",
"uri": "spotify:episode:36SMkU9lPQUq85NQQBWET7"
}
],
"limit": 50,
"next": "https://api.spotify.com/v1/shows/2yB9jTRog4XGCKG5bpNZUA/episodes?offset=50&limit=50&market=FI",
"offset": 0,
"previous": null,
"total": 63
},
"explicit": false,
"external_urls": {
"spotify": "https://open.spotify.com/show/2yB9jTRog4XGCKG5bpNZUA"
},
"href": "https://api.spotify.com/v1/shows/2yB9jTRog4XGCKG5bpNZUA",
"id": "2yB9jTRog4XGCKG5bpNZUA",
"images": [
{
"height": 640,
"url": "https://i.scdn.co/image/d8654ac47ca21c03372a05a62c31ffcc52019e71",
"width": 640
},
{
"height": 300,
"url": "https://i.scdn.co/image/016737ee1188f0eb34284e0b86761f52c097b0fc",
"width": 300
},
{
"height": 64,
"url": "https://i.scdn.co/image/92b4b89483a4463f124db85fe4874caae814c81c",
"width": 64
}
],
"is_externally_hosted": false,
"languages": [
"en"
],
"media_type": "audio",
"name": "The AIAS Game Maker's Notebook",
"publisher": "The Academy of Interactive Arts & Sciences",
"total_episodes": 63,
"type": "show",
"uri": "spotify:show:2yB9jTRog4XGCKG5bpNZUA"
}