Always use the merge field drop-down to add Fake Audits to your emails!
The second common issue is something we cannot fix on our side, and it's website taking too long to load or being a dead link.
There's no real solution to this one, as it's simply impossible for our screenshotter to capture it. This also applies to websites having certain scripts installed that block software such as our screenshotter, resulting in it being a blank image.
As long as the image is being shown (having a play button on top of something) means that your setup was correct, it's just that the website you're trying to target cannot be captured at the time. Simply try testing with a different lead.
Special Case: There were a few cases where the email was opened too fast, and the image was still in upload process. This happens very rarely, but is worth noting.