Cannot Convert a PDF to Black and White Using the Print Function

[ap25_9711]

Hello everyone! I am using Adobe Acrobat Standard (Version 2024.003.20180 64-Bit).

I just went through the whole guideline on "How to make a PDF Black and White".

https://www.adobe.com/uk/acrobat/resources/pdf-to-greyscale.html

Unfortunately, it always fails, the document in colour could NOT become B&W in any way.

Has anyone encountered this issue/problem lately?