Hi lak_2011,

Thanks for followup.

It is important that whether the wordpress target site is also controlled by you(you can add code logic on it)? If not, I'm afraid that what we can do is quite limited. Sharing cookie between web sites (under different domain) is prohibited due to security reason (for most mainstream browsers). And for such scenario, your web app and the wordpress web app need to define a custom authentication process for them to communicate with each other. Such as use querystring to pass some encrypted security token which can be used for verify if the current user has been authenticated or not.