Thank you for reaching out, and sorry to hear that you are experiencing this issue.
Could you please provide more details about the workflow that leads to the black pop-up window? It would be very helpful if you could share a video demonstrating the steps you take and what happens during the process. Additionally, please include the versions of Acrobat and your operating system that you are currently using.
How are you trying to open the PDF? Are you trying to open it with Acrobat, or with your web browser? Which web browser(s)? What type of computer (Mac, Windows PC, Mobile Device), using which operating system?
We want to help, but we need a lot more information from you before we can. Please provide some answers to these questions, which will help us help you by narrowing down the particulars of your issue and what steps may need to be taken to fix it with you.