Unable to attach PDF to a Gist

Hi GitHub Community,

I am new to the GitHub and in the process of creating my first Gist. I have been trying to attach a PDF but I keep getting an error message saying that the file type is unsupported (see below).

According to this GitHub help article, PDF file type is supported and my file size is 800 KB which is well below the supported limit. PNG, JPG, MP4, DOCX and XLSX files attach without issue.

Is there something that I am missing which is preventing PDF’s from being attached?

Many thanks in advance for your help.

Tim B.

I can confirm that it is possible to attach a PDF to a comment in GitHub so the issue seems limited to Gists only