Redirect issues

Hi I have a private page like:

https://www.mydomain.com/private-page

When checking if a user is logged it throws the signed in user out thinking they are not logged in, but if you manually change the url in the browser bar to the below it works it lets them in :

https://www.mydomain.com/private-page/

The plugin doesn’t seem to add the slash at the end and so causes problems. Is it possible to make it add it? Or is there another way to deal with this issue?

Thanks