.pdf recipients receive message saying they don't have permission to print document

I apologize in advance for my lack of tech knowledge. I have been having an issue for several months now and can’t really find a conclusive answer.

I create and sell .pdfs. I have to secure those .pdfs to ensure people can’t pull fonts and clipart from the .pdfs because it is a violation of the terms of use for the fonts/clipart.

I only want buyers to be able to print, NOT edit my .pdfs. I create the .pdfs in Canva then use Adobe Acrobat DC to secure them. I was taught to make the following selections to secure:

“Protect”
“Advanced Options”
“Encrypt with Password”
“Restrict editing and printing of the document. A password will be required in order to change these permission settings.”

“Printing Allowed”
“High Resolution”
“Enable text access for screen reader devices for the visually impaired”
Then under “options” I choose “Acrobat 7 and later” and “encrypt all document contents”
Then I type in a password, then again to confirm and then save the .pdf

I have been doing this since March 2021. I was initially choosing “Acrobat X and later” and someone suggested the person printing might not have the latest version so I might want to consider choosing an option that goes back a little further.

About once every two weeks I hear from a buyer who says they get a message they don’t have permission to print. Other buyers have purchased these same products and don’t seem to have a problem. Some buyers only use the .pdfs digitally and don’t have a need to print.

Am I doing something wrong on my end? And if so, what do I need to change? If it’s not on my end, what is happening on their end, and what can I tell them to do in order to fix it? I can’t seem to find any kind of consistency because I have no way of knowing who is printing, who isn’t, how they are trying to view and print the document, or what kind of device they are using.

Any ideas on what the problem(s) might be? HELP, PLEASE! I need to be able to give troubleshooting options when this happens and I don't know how to help them.