Logout REST method returning 'Session expired or invalid

Hello, 

We have an app that logs into a rollbase session, gets a few pieces of information, then logs out. Everything works great until the logout part. Here is my code and subsequent error and output.

diyLogout: function (success, error) {
     logWriter.writeLog("model.js",0,"diyLogout");
     var data2 = {
     "sessionID": dmsi.model.session.diySessionID,
     "output": "json"
     };
     this._ajaxCall2("GET", "logout", data2, success, error);
},

_ajaxCall2: function (type, method, data, success, error) {

    var rollbaseUrl = dmsi.config.rollbaseSettings.baseUrl + method + '?' + $.param(data);

    var options2 = {
    url: rollbaseUrl,
    contentType: 'application/json',
    success: function (rsp) {
    success(rsp);
          }
    }

    $.ajax(options2).fail(function (err) {

         logWriter.writeLog("model.js",0,"ajaxCall2 failed");

         console.log(err);
     });
},

diy.dmsi.com/.../logout 403 (Forbidden)
Object {readyState: 4, responseText: "{ "status": "login", "message": "Session expired or invalid login credentials" }", responseJSON: Object, status: 403, statusText: "Forbidden"}

I've triple checked the session id against the user access log so I know it's valid. Now, that user was already logged in so rollbase kicked the previous one out. Could that be the cause? This should be about as straight forward as it gets so what am I missing?

Thanks