Error - 12300 Invalid Content-Type

[Hamza123Imran]

Hi, i have implemented audio call in my iOS App with backend server of php. I'm getting the access token from the my server and than uses all the delegates , as per following the steps of twilio swift project. Now when i make a call, it successfully registered my push credentials first, than on click of call button it first show ringing in my console and than call fails. When i check my voice dashboard on twilio i get this error,
Twilio is unable to process the Content-Type of the provided URL. Please see the Twilio Markup XML Documentation for more information on valid Content-Types.
You must return a Content-Type for all requests. Requests without a Content-Type will appear in the Debugger as a 502 Bad Gateway error., These are the parameters that comes in the API,
`

ApplicationSid	"APaecd77856d0049b8b80baa3c41f193a2"
ApiVersion	"2010-04-01"
Called	""
Caller	"client:alice"
CallStatus	"ringing"
to	"+923244544783"
From	"client:alice"
To	""
CallSid	"CA98977f223a883f16b3585165066adde1"
Direction	"inbound"
AccountSid	"ACbc55b9853285730abd137444750e53c6"

I'm making client to client call through phone number. In identity i pass my phone number and in to i pass . other client phone number. I'm confused that why it is failing the call. Showing this error in my console, [VERBOSE TVOCall] handlePJSIPInviteStateDisconnected. Error: Error Domain=com.twilio.voice.error Code=603 "Connection error (603)." UserInfo={NSLocalizedDescription=Connection error (603).,

[bobiechen-twilio]

Hi @Hamza123Imran

I've run the Call SID in the database and found that actually the TwiML response from your app server is actually empty thus the call resulted in the error. Please check that the app endpoint provided for your App SID is up and running and returning valid responses.

Thanks.
-bobie

[Hamza123Imran]

Thanks for your quick response, we have checked that our TwiML have a verb and some text in it. whenever we hit the Url from postman it gives us a call and that verb works and speaks the the text but the error comes only when we run the app and try to call. Can we provide you our URL that we are using for call and giving in our TwiML app? So that you can test it for us as we are unable to understand the problem. We are providing the to n from numbers correctly.

[bobiechen-twilio]

Hi @Hamza123Imran

I checked the Call SID again and from the error message I think you might want to check the URL provided in the TwiML application. It seems that you put the same link twice thus when the Twilio Voice service is trying fetch the TwiML, it tried to hit an URL that is in incorrect format.

-bobie

[Hamza123Imran]

Hi @bchen-twilio , let me clear you the procedure that i'm doing for the call, First of all as my backend is in php. I hit and API to fetch the token from my backend server. These are the parameters that is send in an API, let param = [ "token" : LoginToken!, "identity" : myPhoneNumber! ] as [String : Any] . When i hit this i get accessToken from the my server. This accessToken further on i pass to different delegates in a code to make call. As i have followed your code.
Now in this delegate where we pass our parameter 'to' and 'from' ,
func performVoiceCall(uuid: UUID, client: String?, completionHandler: @escaping (Bool) -> Swift.Void) { let accessToken = UserDefaults.standard.string(forKey: "voiceToken") if accessToken != nil { print(accessToken!) }else { completionHandler(false) TwilioVoice.logLevel = TVOLogLevel.verbose TwilioVoice.setModule(TVOLogModule.PJSIP, logLevel: TVOLogLevel.verbose) return }

    let parameteres =  ["To" : otherUserNumber,
                        "Caller" : myPhoneNumber,
                        "From" : myPhoneNumber,
                        "from" : myPhoneNumber!,
                        "to" : otherUserNumber
                        ]
    print(uuid)
    
    print(parameteres)
    call = TwilioVoice.call(accessToken!, params:parameteres as? [String : String] , uuid:uuid, delegate: self)
    print(call!)
    self.callKitCompletionCallback = completionHandler
}`. 

This is what i'm passing in the parameter in 'to' the other user phone number and in 'from' i'm passing my number. When it hit from app first it shows status ringing in console and than fails to call.
But when i hit same API in postman like this,
[https://drive.google.com/drive/folders/1nSvrcP4V0Er3ii5kGHRpF7X_2iEnVYuJ?usp=sharing(url)
The call goes properly and when we receive the call we hear congratulation message. But on app the call fails and we not even get a congratulation call. Why it is failing in app, i have check the URLof TwiML also.
I'm confused in one thing , that how we can make client to client call , and if one client say anything how will that get in response or hear to another client? How to pass the live voice in response?

[bobiechen-twilio]

Hi @Hamza123Imran

Directly to your last question, which i think should be the main goal for your app integrating the Voice iOS SDK: if you take a look at makeCall.php you will see to make a client-to-client call you can just use the $dial->client($to); line. The callee client needs to be registered with that identity to be able to receive the call notification (which I believe you already did) and accept the call-invite, then the audio should be flowing between the caller and callee once the call is connected.

[Hamza123Imran]

we have implemented makeCall.php on our server side, the code is in this link http://softdepth.com/projects/raven/customer/audiocall with to,from,token params. When we hit this url on postman we receive call with the same message that is written in TwiML xml file.

Now when we hit the this method in ios app

let parameteres = ["To" : otherUserNumber,
"Caller" : myPhoneNumber,
"From" : myPhoneNumber,
"from" : myPhoneNumber!,
"to" : otherUserNumber
]
print(uuid)

    print(parameteres)
    call = TwilioVoice.call(accessToken!, params:parameteres as? [String : String] , uuid:uuid, delegate: self)
    print(call!)
    self.callKitCompletionCallback = completionHandler

it query on Twilio server starts ringing and after couple of seconds it show error and the error comes in our Twilio Debugger console.

Can you please help in setting up the flow of call from ios to ios app if we are missing something? and guide us in details how Twilio call works and how we have to make our TwiML to make a simple call with Twilio VOIP? may be we are unable to understand the proper flow. We are stuck here and our work is pending. Kindly help us in understanding the documentation for us, its a bit confusing.

[bobiechen-twilio]

Hi @Hamza123Imran

Sorry for the delay.
I checked the Account SID and for some reason I still saw couple of errors (2018/9/18) indicating that the URL specified in the Voice incoming request doesn't seem to be correct.
Also if you believe the response from your makeCall.php endpoint is correct, the response should look like this:

<?xml version="1.0" encoding="UTF-8"?>
<Response>
    <Dial callerId="14081234567">
        <Client>bobie</Client>
    </Dial>
</Response>

Let me know if this helps.
-bobie

[Hamza123Imran]

Hi i have check my url for makecall on postman it is showing me same response as you said above,
We Follow up following steps

1. Audio token generated from PHP API here is screenshot how we are generating audio token http://prntscr.com/kydp1s
2. After getting token from PHP we are calling voice delegate in IOS please check screen shot http://prntscr.com/kydpz6
3. Twillio App hit makeCall API which mention here http://prntscr.com/kydrq6
4. And makeCall API returning correct response http://prntscr.com/kydsf2
5. here is the code inside makeCall API function http://prntscr.com/kydt58
   Now can you identify that where we are making mistake? Because response on postman is right but when hit on voice dashboard it shows content type error?

[bobiechen-twilio]

Closing this issue for now. @Hamza123Imran please feel free to re-open or create a new issue in the future.

Thanks,
-bobie