By default, iOS browsers block popups.
As we open a new tab when we generate a PDF for your prescription, labs or other notes, the browser will block that as well.
Here's what you need to do:
SAFARI
Go to Settings
Tap Safari
Block Pop-ups > Disable the toggle (it should be gray)
Go to Safari and download the prescription. It will work now.

CHROME (iOS)
Tap the 3 dots
Tap Settings

Tap "Content Settings"

Disable "Block Pop-ups" (Gray Color)
Tap Done

Download the prescription and it will now work.