Why did I get the message "Page contains both secure and nonsecure items" when redirected to the PayPal page?
When you're redirected to the PayPal page, you see a pop-up message stating "This page contains both secure and non secure items. Do you want to display the non secure items?"
Your own image or logo is included on the PayPal pages, but the image file isn't on a secure (https) server. All of the PayPal site content is on secure (https) pages, so any of your content stored on a non-https URL will cause this error message.
To correct this issue, host your images on a secured server so that the URL of the image begins with the https:// prefix.
If you have SSL enabled on your web server already (if you already have https:// pages), then you can change the image URL in your code from http://<pathToImageFile> to https://<pathToImageFile>.
If you don't have an SSL-enabled web server, consider third-party hosting of the image on a secured server.