Hi Soliman,

The end-user will not get the whole message; he will get only the below part:

Because you logged in as a developer, so you are getting the whole message, which not looks good.

But still, if you want to redirect to another page, you can use the same PL/SQL function (you used for the authorization scheme) on page load to set a page item value. Then on the change event of that page item, you can redirect to another page using JavaScript.

For example, create a dynamic action on page load to execute PL/SQL code. Now in that code, check with that same function, and if it returns False, then set a hidden page item value to 0. If returns True, then set the hidden page item value to 1.

Now create a dynamic action on hidden page item on change event to execute JavaScript. Specify client-side condition item = value. Set value to 0.

Create a True action to execute JavaScript code and add the following code to redirect to another page:

apex.message.alert( "You are not authorized to access this page.", 
function(){
   javascript:window.open('f?p=&APP_ID.:1:&APP_SESSION.:::1', '_self');
});

The above JavaScript code will redirect to the home page after giving the error dialog message.