Occasional Attachment Preview Error in Comcast Webmail (PDF and JPG)

I'm experiencing an intermittent issue with Comcast webmail when previewing attachments.

Most often, this occurs with PDF files: when I click to preview a PDF attachment (either before sending or after receiving), I sometimes get the error message:

"An error occurred while loading the document so it cannot be displayed. Please download the file using the button below."

The files are typically small (e.g., 120KB), open fine on my PC, and are standard PDFs. I tested this in both Edge and Firefox, and the error occurs in both browsers.

I also occasionally see this error with .jpg image attachments, though less frequently. For example, a 76KB JPEG previewed fine, but a larger 1.7MB photo showed inconsistent orientation before and after sending (landscape before, portrait after).

I could not reproduce the error today with a JPEG, but I’ve seen it enough times to know it’s not isolated.

Is this a known issue with Comcast’s preview engine? Are there recommended file formats, size limits, or encoding practices to avoid this error?

Thanks in advance for any guidance or insight.