SPfx Extension app didn't showed up after deploy

[rizaldirpamungkas]

I've developed 2 SPFx extension app for my office, one is already deployed and used while one is still in development. While I was trying to deploy my under development app to SharePoint UAT site for testing it works well no error both in gulp serve or while building the solution for it but after I uploaded it to SharePoint and added it to the site I can't seem to see the command extension that I've developed there. After that I tried again with really vanilla template of command extension and deploy it straight away and still I see no changes in the site. Any advise would be helpful