Hello,
Thanks for your message. We suggest getting in touch with our team through our website for issues related to the commercial version of the plugin, or this conversation will be off-topic on this forum. We even speak the same language, so please get in touch with our team by using the contact form on our website, or better by opening a support ticket from our support hub.
Usually, “Restricted Area” messages are displayed whenever the user role and capabilities aren’t sufficient to open a specific page. It may be possible that the landing page after completing a reservation has got special access restrictions defined through WordPress.
We suggest checking the URLs of the various landing pages before and after completing a payment to understand what exact page may have access restrictions. Moreover, testing the payments from an incognito session of your browser with no login data is always recommended.
Thank you,
The VikWP Team