Surely if Twitter Sign On has been enable then 'Did you want to Use Single Sign On?' should be set to true for that user during the account creation process otherwise it's a pointless exercise?

Any help would be appreciated.

YAF Version 1.9.6.1

The default value is set to true also when register via Facebook.

My only guess is that the registering was not complete, maybe an exception that stops the process. Did you get an pm and dm after registering?

Ok if you don't receive any DM the registration process wasn't completed. Was no error message shown during setup?

I will add some logging to the event log if something goes wrong.

Server Error in '/' Application.

The remote server returned an error: (401) Unauthorized.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Net.WebException: The remote server returned an error: (401) Unauthorized.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[WebException: The remote server returned an error: (401) Unauthorized.]

System.Net.HttpWebRequest.GetResponse() +7864708

YAF.Core.Services.Twitter.OAuthTwitter.WebResponseGet(HttpWebRequest webRequest) +281

YAF.Core.Services.Twitter.OAuthTwitter.WebRequest(Method method, String url, String postData) +292

YAF.Core.Services.Twitter.OAuthTwitter.OAuthWebRequest(Method method, String url, String postData) +1155

YAF.Core.Services.Twitter.TweetAPI.SendDirectMessage(ResponseFormat reponse_format, String screen_name, String message) +289

YAF.Core.Services.YafSingleSignOnUser.SendRegistrationMessageToUser(MembershipUser user, String pass, String securityAnswer, Int32 userId, OAuthTwitter oAuth) +1227

YAF.Core.Services.YafSingleSignOnUser.LoginTwitterUser(HttpRequest request, String& message) +1700

YAF.Auth.Page_Load(Object sender, EventArgs e) +343

System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +25

System.Web.UI.Control.LoadRecursive() +71

System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3064

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.272

Take a look at the application settings of your twitter app is it set to "Read only" under Application type? It needs to be set to "Read and Write"