Hi there,
Could you share the screenshot of what is displayed when you try to download via PNG? What mobile OS are you encountering on (iOS/ Android)? Are you getting any error messages?
The feature still exists; please refer to the screenshot for the web app.

Also, for desktop (Web app), you may try the following steps:
- Try signing out and then signing in again.
- Using Incognito or private browser mode.
- Trying after clearing the cache and cookies of the browser.
- Rebooting the machine.
Let us know how it goes; we are here to help just need some more info.
Thanks
Amitej