Cannot download PDFs.

I am a BIOMEDICAl ENGINEER trying to download documents for an infusion pump and I keep getting a error message that the file is corrupt or unreadable. This has happened with five different sites for three different files.

Any idea what's up with this? My phone is a Galaxy S20 with latest software running on Verizon 5G.

Alex Robinson BIOMEDICAL ENGINEERING DEPARTMENT Afya Foundation of America