Problem while accessing campaign data in facebook using .net

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ASP.NET

i m developing facebook integration with .net

https://graph.facebook.com/app?access_token=124638494284029|9kz1fxXZH0lIj2CW0dfeHmx_OGA[^]

this link is working

but when i m accessing campaign data using
https://graph.facebook.com/act_44815699/adgroups?campaign_ids=[6004834379123]&access_token=124638494284029|9kz1fxXZH0lIj2CW0dfeHmx_OGA[^]

it throw error

{
   "error": {
      "message": "(#294) ",
      "type": "OAuthException",
      "code": 294
   }
}

any idea how to resolve this error