PDF corrupt/invalid

I just installed this and would love to use it. However, the first PDF that I tried–which displays fine in its own browser tab–throws an error in the reader: https://viewpoint.kinsta.cloud/wp-content/uploads/Guidance-on-Vaccines_ViewPoint.pdf
The error text says the PDF is invalid or has errors. I know its a valid PDF, but is there something I’m missing about PDF standards or size limits?