Problem linking Photo (from external server) to external URL

I’ve been searching online forums for quite a while and have yet to find a solution to my problem.

We have all of our photos stored on Amazon S3 Storage and do not use the WordPress image gallery. We have no issues inserting images into a post, but when we try to link the photo to an external URL when clicked on, we get a pop-up which states “The image cannot be loaded. Make sure the path is correct and image exist.”

On RARE occasions when I try to mess with the code and preview the post, I click on the image, a new window opens and the correct linked site opens. If I close that window and immediately try to click the same image again, the error message pop-up shows up again despite having worked 10 seconds prior.

When inserting photos, I click the “Add Media” button, select the “insert from URL” link, paste the image link from the Amazon server. I’ve tried using the “Link URL” field when opening the image editor, but this does not work. I’ve even entered the code independently from the “insert media” button and I get the same error message.

All of the forum topics I have found related to this only deal with photos in a WP image gallery, not from an external URL. I would appreciate any and all assistance with this. If you need additional specifics or information, please let me know.

Thanks in advance for your help!