This problem is caused by not verifying the PDF signature, which can be solved by enabling related functions. The steps are as follows:

1. Directly in the main interface of Acrobat Reader, select to open the edit menu.

2. If there is no problem at this time, continue to click the icon button to jump.

3. Next, a new window will pop up, and you need net safe settings.

4. In this way, the inspected object is determined and the requirements can be realized.