Invalid Token When Using Alamofire - oauth-2.0

Question

Environment: Swift 2, iOS 9
I had rolled my own HTTP networking library. It wasn't broken but I decided to fix it and switch to Alamofire.
Here is my code snippet:
case .HTTPTokenAuth: // Token Auth
let dictionary = Locksmith.loadDataForUserAccount("Auth_Token", inService: "KeyChainService")
let token = dictionary!.valueForKey("access_token")
var aManager = Manager.sharedInstance
aManager.session.configuration.HTTPAdditionalHeaders = ["Authorization": "Bearer \(token!)" ]
aManager.request(method, requestURL!, parameters: parameters, encoding: .JSON).response { request, response, data, error in
print("===== Request ================")
print(request!.allHTTPHeaderFields!)
print("===== Response ================")
print(response!.allHeaderFields)
print("===== Error ================")
print(error)
}
The problem is that for some reason the Oauth token is not making it into the header. (At least that is what appears to be the problem as I don't see it in the Request header. I receive the following request/response:
===== Request ================
["Content-Type": "application/json"]
===== Response ================
[Content-Type: application/json,
Www-Authenticate: Bearer realm="Doorkeeper",
error="invalid_token",
error_description="The access token is invalid",
Pragma: no-cache, X-Runtime: 0.002205,
X-Powered-By: Phusion Passenger 4.0.14, X-XSS-Protection: 1; mode=block, Server: nginx/1.6.2 + Phusion Passenger 4.0.14,
Transfer-Encoding: Identity,
Cache-Control: no-store,
Date: Tue, 01 Sep 2015 18:54:16 GMT,
X-Request-Id: 395d2154-5054-423c-a7bc-f7ef85e0cdbf,
Connection: keep-alive,
X-Content-Type-Options: nosniff,
X-UA-Compatible: chrome=1,
Status: 401 Unauthorized,
X-Frame-Options: SAMEORIGIN]

Answer 1

I went with the simpler approach:
case .HTTPTokenAuth: // Token Auth
let dictionary = Locksmith.loadDataForUserAccount("Auth_Token", inService: "KeyChainService")
let token = dictionary!.valueForKey("access_token")
let headers = ["Authorization":"Bearer \(token!)"]
Alamofire.request(method, requestURL!, parameters: parameters, headers: headers, encoding: .JSON)
.response { request, response, data, error in
print(request!.allHTTPHeaderFields!)
print(response)
print(error)
}