Cannot open / view PDF in mobile browsers

[sunidy]

The current stable version 4.3.136 cannot open PDF in mobile brows.

I tested it under iOS and Android with Safari and Chrome.

The PDF 1 link on the page https://test2.bannersky.com/bsk-pdf-manager/ use the old version 4.3.136, it CANNOT be open.

The PDF 1 link on the page https://wangjingtang.com/bsk-pdf-manager/ use the old version 4.0.379, it CAN be open.

Is there an issue or some settings need to be changed?