Exception of type Microsoft.SharePoint.SoapServer.SoapServerExceptio n was thrown

I got an error while trying to add user to a group in SharePoint 2010.

Web_Reference.UserGroup userGroup = new Web_Reference.UserGroup();

            userGroup.Credentials = System.Net.CredentialCache.DefaultCredentials;

            userGroup.Url = @"URL Of the Site/_vti_bin/UserGroup.asmx";

            string groupName = "Employees";

            string userName = "Bijay";

            string userLoginName = "Bijay";

            string userEmail = "myemail@gmail.com";

            string userNotes = "User Added from Client tool";

            userGroup.AddUserToGroup(groupName, userName, userLoginName, userEmail, userNotes);

           

             //same way you can also remove user from the group by using the following object model.

           

            userGroup.RemoveUserFromGroup(groupName, userLoginName);

After executing the error I got the following error

System.Web.Services.Protocols.SoapException: Exception of type 'Microsoft.SharePoint.SoapServer.SoapServerExcepti on' was thrown.

But when I updated the strings to the following format that works for me.

            string userName = "Bijay Kumar";

            string userLoginName = "domain name / sahoobij";

            string userEmail = "myemail@domainname.com";

still I am not sure whther it is the right solution or not but I solved the issue.