Can't print PDF in Nextcloud

The user opens PDF with Nextcloud (WebUI) and tries to print.

Case by Desktop PC:
When using the printing function of the web browser, normal printing such as unintended reduced size printing is difficult.
It does not print when printing from the printer icon on the opened PDF file screen.

Case by iPhone:
It does not print when printing from the printer icon on the opened PDF file screen. Even the print setting screen does not appear.
In the case of printing from the action button in the web browser of the iOS device, printing becomes like a screen shot that includes the Nextcloud UI.
In other words, user can not print PDF files on the iPhone.

Is there a way to easily print PDF files?


Nextcloud 15.0.5 | Windows10, Firefox 6x, Vivaldi 2.3 | iOS 12.1.x, Safari