When I'm logged in as an administrator and I go to preview protected content on my site I'm redirected to an error page.
MemberMouse enables you to preview your site as different members with different access rights by using the preview settings bar. In order to view protected content you need to make sure that the preview settings are configured to a membership level, bundle or position in a drip content schedule that allow you to view the content otherwise you'll be redirected to an error page just like a normal visitor would if they didn't have sufficient access rights.
IMPORTANT: Sometimes even if the preview settings bar is displaying particular access rights in the drop downs these settings may not be used when rendering the page because the cookies which store the settings are out of date which results in being unexpectedly redirected to an error page. To resolve this, just click the button to recommit the settings and refresh the cookies.
If you continue to receive the error page after clicking Save, then your browser is simply reloading the error page. You should go back to your WordPress editor, copy the URL of the page you want to preview, open another tab and paste the URL into it. If you continue to receive the error page after clicking Save, then your browser is simply reloading the error page. You can then manually enter in the URL of the page that you would like to visit.
Read this article to learn how to preview your site using the preview settings bar.