We are having a global issue with Facebook Ads. The issue is that we have vendor limitations to generate Desktop Previews. When exporting to pdf, Desktop previews don't show up on several instances for several clients. This issue is happening for the Desktop Preview metric of Facebook Ads → Ads Data View. This is affecting the automated reports. This issue has been reported to Facebook via the FB developers portal but they haven't come up with a solution yet.
Several clients are being affected. If you are one of those clients, we would encourage you to comment on the Facebook ticket above, and reach out to your Facebook representative.
Since this is a Vendor bug, we will need Facebook to fix this issue and with not much of a response from their end, we are looking for different ways and channels through which we can escalate this to achieve faster resolution from the Vendor.