Please help - After viewing a PDF in the browser, I cannot open it in the application.

The following problem is occurring. Please let me know the cause and solution.
1) Open a PDF file in the Chrome browser on the Chromebook.
2) When I click on “Open in Apps” and select “Adobe Acrobat: PDF editing, conversion, and signature tools,” I get the error message "The file could not be opened with this app because the app is not approved. Please try again." and an error message appears and the PDF cannot be opened.