php - An unknown error has occurred Facebook Page feed only very recently -

i getting error message

{ "error": { "message": "an unknown error has occurred.", "type": "oauthexception", "code": 1, "fbtrace_id": "" }

while fetching page feed using facebook page feed using curl. working fine till recently. 1 if there changes or how figure out.

i believe facebook has made changes access token. right.

code send curl below after getting accessing token , response show below

message: file_get_contents(https://graph.facebook.com/v2.7/{page id}/feed?fields=id,story,permalink_url,from,name,message,picture,created_time,likes.summary(true),comments.summary(true).limit(50),shares&until=1491434308&since=1490829508&{"access_token":"{token id} |{token id part}","token_type":"bearer"}): failed open stream: http request failed! http/1.1 400 bad request