UnityWebRequest has already been sent; cannot begin sending the request again

Question

I'm trying to regenerate token from server using golang When I host this url in localhost i get rtc and rtm token both in chrome site http://localhost:8080/rte/agora/publisher/uid/1234/

Later I tried to connect with unity this is my webrequest in unity

public static class HelperClass
{
    public static IEnumerator FetchToken(string url, string channel, int userId, Action<string> callback = null) 
    {
        Debug.Log("Hitting Web Request");
        UnityWebRequest request = UnityWebRequest.Get(string.Format("{0}/rtc/{1}/publisher/uid/{2}/", url, channel, userId));
           
        yield return request.SendWebRequest();

        if (request.isNetworkError || request.isHttpError) 
        {
            Debug.Log("request"+request.error);
            callback(null);
            yield break;
        }

       TokenObject tokenInfo = JsonUtility.FromJson<TokenObject>(request.downloadHandler.text);

        callback(tokenInfo.rtcToken);
    }
}

this is my url i tried to get

internal static string _tokenBase = "http://localhost:8080/rte/agora/publisher/uid/";

and I run this using

StartCoroutine(HelperClass.FetchToken(_tokenBase, _channelName, 0, this.RenewOrJoinToken));

I tried to get auto generate token but I'm getting below issue

InvalidOperationException: UnityWebRequest has already been sent; cannot begin sending the request again
UnityEngine.Networking.UnityWebRequest.SendWebRequest () (at /Users/bokken/buildslave/unity/build/Modules/UnityWebRequest/Public/UnityWebRequest.bindings.cs:266)
Agora.Util.HelperClass+<FetchToken>d__0.MoveNext () (at Assets/Agora-RTC-Plugin/API-Example/Tools/RequestToken.cs:27)
UnityEngine.SetupCoroutine.InvokeMoveNext (System.Collections.IEnumerator enumerator, System.IntPtr returnValueAddress) (at /Users/bokken/buildslave/unity/build/Runtime/Export/Scripting/Coroutines.cs:17)

Answer 1

Sounds like the Coroutine is firing twice. Attach the debugger and set a breakpoint inside the FetchToken coroutine and see whether it fires twice (and check the callstack to see where from and inspect why).