Facebook caches the contents of a page for a long time, so the changes you make are not always updated immediately. You can use the Facebook debug tool to refresh the content.
Enter the Donorbox donation form URL and click Debug.
Click the Scrape Again button.
Note: If you want to share your website page with the donation widget embedded, you need to add open graph tags to the page in order to display the required information when shared on Facebook or other social media sites.