If you are experiencing an issue with the KWIZ Classic app(s) are not appearing on the list ribbon even after reinstalling it, please follow the steps below:

Remove the KWIZ Classic app(s) from site contents:

1. Go to your SharePoint site and click on "Site contents". Make sure you are in the "Classic SharePoint" experience. If not, please switch it by clicking on "Return to Classic SharePoint" link in the bottom  left corner.
2. Find the KWIZ Classic app(s) and click on the ellipsis icon
3. Click on "Remove" to remove the app from the site

Once the app is removed, Re-add  KWIZ Classic app(s) to the site:

1. Click on "Add an app" in the site contents page.
2. Click “From Your Organization” link on the left side where you will see KWIZ Classic app(s) 
3. Click on "Add" to add the app to the site.

Wait for the "ghost" version of the app to fully remove itself:

1. When the app is adding, you will see two "ghost" versions of the app, one being added and the other being removed.
2. Cancel the app that is being added to the site.
3. Wait for the "ghost" version of the app to fully remove itself.

Once the app is gone from Site Contents, add the app to the site one more time.

You will only see one copy of the app within Site Contents, and once it has finished adding, the app icon will now be available within the list ribbon.

By following these steps, you should be able to resolve the issue with the KWIZ Classic app(s) not appearing on the list ribbon.