We also are not able to edit product from the frontend of a different website which is on the same magento installation with the main website that we install the module. They are multistores.
Could you please get the download link HERE for the updated version that will fix your issue and re-install it on your site?
For more information about product, please refer Admin Product Preview Plus page.
If you need any further assistance, please feel free to contact us.
Please visit our site for more useful Magento 2 Extensions: https://bsscommerce.com/magento-2-extensions.html