after update to ios10, Alamofire4 request brings error status 401 - alamofire

Question

After updating to xcode8 Alamofire4, my AlamofireRequest is not working, returning " status code: 401, headers" (unauthorised) on the request. The user authorisation is correct (I have checked the site). I do not have any compiler errors, but note that 'headers' is not highlighted in blue as usual, so am thinking that it is not recognising the headers properly. Am I doing something wrong with the 'headers' here?
let user = "sampleUser"
let password = "samplepass"
let credentialData = "\(user):\(password)".data(using: String.Encoding.utf8)!
let base64Credentials = credentialData.base64EncodedString(options: [])
let headers = ["Authorization": "Basic \(base64Credentials)"]
var checkUserEndpoint: String = "https://sample.com/ios1/user/\(uidEntered!).json"
print(checkUserEndpoint)
Alamofire.request(checkUserEndpoint, method: .get, parameters: nil, encoding: JSONEncoding.default, headers : headers)
.responseJSON { response in
print(response.request)
print(response.response)
print(response.data)
I have already tried using this instead for the headers, but it made no difference:
var headers: HTTPHeaders = [:]
if let authorizationHeader = Request.authorizationHeader(user: user, password: password) {
headers[authorizationHeader.key] = authorizationHeader.value
}
also I tried this and it made no difference;
Alamofire.request(checkUserEndpoint,
method: .get,
parameters: nil,
encoding: JSONEncoding.default)
.authenticate(user: "sampleUser", password: "samplepass")
.validate()
.responseJSON { response in
print(response.request)
print(response.response)
print(response.data)
// print(response.error)

Answer 1

I've done similar migration twice, and my educated guess is that one of your strings you pass to generate headers value is Optional, ie. user, password or base64Credentials; though generating Optional("thestring") instead "thestring". You can try to wrap the request like this:
if let user = user, password = password, base64Credentials = base64Credentials {
let headers = ["Authorization": "Basic \(base64Credentials)"]
var checkUserEndpoint: String = "https://sample.com/ios1/user/\(uidEntered!).json"
print(checkUserEndpoint)
Alamofire.request(checkUserEndpoint, method: .get, parameters: nil, encoding: JSONEncoding.default, headers : headers)
.responseJSON { response in
print(response.request)
print(response.response)
print(response.data)
}
This can happen eg. in a situation, where those values coming from the Objective-C code, where the variables are not marked nonnull.
... base64Credentials should not be optional though, as stated in the documentation.

Answer 2

The code is correct in both variants (manual header creation and Alamofire request .authenticate usage). Looks like server side issue, use curl/postman or any other REST client to receive success response from your server before continuing your app development.