How to get ALT Text from Instagram Graphql API?

Question

I'm trying to get alt text of a picture on instagram, but the following endpoint does not work

https://www.instagram.com/graphql/query/?query_hash=b3055c01b4b222b8a47dc12b090e4e64&variables={
  media_object(id: "C4SqQlcMX20") {
    caption
    media_type
    media_url
    thumbnail_url
    permalink
    timestamp
    username
    accessibility_caption
  }
}

I get this message:

{"errors":[{"message":"execution error","severity":"CRITICAL"}],"status":"ok"}

What Am I doing wrong?