Proton mail app does not give a download option for attachments, like gmail, etc. I get a .pdf attachment, and proton says I can't open it. I can open pdf files on my phone, but when I try to open a pdf attachment in proton mail, it says no app can perform this action. If I cant download it, I can't open it. Should I have to use another email service, or spend a bunch of time trying to get it through drive?