Unable to make PDF/A

Hi!

We are unable to make a PDF/A. We follow the instructions: Open your PDF, navigate to All Tools > Apply PDF Standards, and click Save As PDF/A.

Then, there is a pop-up telling us some components are being installed. After a couple of minutes, we get another pop-up saying we need to install the components manually. When we click on install, it brings us on a page on Adobe that no longer seems to exist (404 error)

I tried to reinstall it completely and search which component I need to install but couldn’t find anything. 

See the following to see what we already tried. Thank you in advance for your help!