SPFx Extensions not showing at customer tenant

Hi Vesa,

Some more details about those extensions:

1. Extensions are successfully deployed to the App Catalog (Site Collection App Catalog)
2. User Actions Features appear in the Site Scope and also in the Site Collection Scope. We have also verified that the Extensions are there, but as I said, they are not being shown. This has also happened with the default extension you get with Yeoman.
3. We don't see any exception when the document library where the extensions are located is loaded and we monitor the console output in the browser developer tools.
4. When you say Disable Public CDN: Do you mean disabling it using PowerShell ? In that case, we cannot disable the public CDN being used since it's being used in other SPFx solutions (WebParts that are working as expected).
5. The package-solution.json file we have for our extension is the following one:

{
  "$schema": "https://dev.office.com/json-schemas/spfx-build/package-solution.schema.json",
  "solution": {
    "name": "process-extensions",
    "id": "4951855a-f6ae-443f-9936-41a5cbb2cd2e",
    "version": "1.0.0.1",
    "includeClientSideAssets": true,
    "features": [
      {
        "title": "Application Extension - Deployment of custom action.",
        "description": "Deploys a custom action with ClientSideComponentId association",
        "id": "37ea889e-3bcc-464b-a297-8f20f6410c3e",
        "version": "1.0.0.1",
        "assets": {
          "elementManifests": [
            "elements.xml"
          ]
        }
      }
    ]
  },
  "paths": {
    "zippedPackage": "solution/process-extensions.sppkg"
  }
}

Also for your reference, the elements.xml file is the following one:

<?xml version="1.0" encoding="utf-8"?>
<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
    <CustomAction
        Title="AddFlat"
        RegistrationId="101"
        RegistrationType="List"
        Location="ClientSideExtension.ListViewCommandSet.CommandBar"
        ClientSideComponentId="8bfb46e3-dff8-4b50-a107-9ccb9a4c964b"
        ClientSideComponentProperties="{&quot;sampleTextOne&quot;:&quot;One item is selected in the list.&quot;, &quot;sampleTextTwo&quot;:&quot;This command is always visible.&quot;}">
   </CustomAction>
</Elements>

What we are going to do is create another public CDN for the extensions so we can apply the troubleshooting steps.

If you see something wrong in the points above, please let me know.

Thanks!