Restrict access to part of Joomla articles

In an attempt to restrict access to part of Joomla articles i have enabled the "Content - Membership Pro Content Restriction" plugin and followed these instructions . View the test article here .

None of the text is hidden and the syntax is visible on the front end.

Please assist.

There is no option to safely add administrator login info. Hidden text?

Hi Paul

Maybe there are some strange characters inserted into {mprestriction} tags and it causes the issue. Please access to joomdonation.com/support-tickets.html , submit a support ticket sending us super admin account of your site. We are going to check to see why it doesn't work and tell you the reason so that you can correct it yourself if it happens again in the future

Regards,

Tuan