string(87) "{"code":"INVALID_TOKEN","details":{},"message":"invalid oauth token","status":"error"} " grtting this error

string(87) "{"code":"INVALID_TOKEN","details":{},"message":"invalid oauth token","status":"error"} " grtting this error

Using access token i am trying to add sales orders through api but it is throwing errors like the above i have mentioned. Please help me for that