Hope you are doing well, and thanks for reaching out.
This issue usually occurs when the source file has been moved, renamed, or deleted from its original location. As a result, Acrobat continues trying to access the file, leading to the problem you're experiencing.
To resolve this, please try the following steps:
Log out of the Acrobat app.
Restart your device to refresh the system.
Log back into the app and check if the issue is resolved.