Receipt page problem

Hi
I have a problem with the receipt page and you suggested me to go to your support forum, but it is easier for me here as I have many screenshots and I usually re-edit my posts after submitting.

Well I have chosen the full-width-page template from my theme for my receipt page. I renamed it donation-receipt-page.php and put it in my child theme.

The first screenshot shows a campaign page with normal URL, so no problem here. It is just to see the URL screenshot

The second screenshot shows the receipt page after clicking for an offline payment. The permalink is not correct as it shows a /wp/, that is the folder where I installed WordPress. I have of course two .htaccess, one in www and another in www/wp but they are exactly the same. So I cant understand the cause of the problem.
screenshot

In the third screenshot I have deleted the /wp/ and reloaded the page.
The new full-width-page template appears but it is empty, while it should show instructions for the payment. I think that I had to insert something in the page, probably to replace the loop part; but I am not sure…
screenshot

I saved the permalinks in the dashboard and I dont know what else to do to make the receipt page work correctly. Please give me clear instructions, step by step to resolve the problem. Except this, the plugin is excellent.

Best regards

https://ww.wp.xz.cn/plugins/charitable/