I cannot view quotations when clicking the "display" button in the admin panel
This issue occurs when the domain name of your store differs from the one you use to access the admin panel of your store.
For example, if your store (customer side) is accessible via the URL: www.monsite.com and you access your site's admin panel using the URL monsite.com/admin (without the www), then the module will not be able to display the quotations from the admin panel.
You must therefore access your site's admin panel using the same domain name as that used by your customers (in the previous example, with the www).
You may encounter the same problem if you access your back office via "http" while the front office of your site uses "https" (and vice versa).