I have set up a sharepoint site with the settings enabled for custom scripts. I have tried to upload a custom.css file in the style library but comes with an error message of access denied. I also downloaded 2 app .sppkg files and uploaded them to my app catalogue in the admin center of sharepoint and deployed to my sites, however when I add the app to my site I do not get access to the webpart attached to that app. App deploys and adds to the site fine but I cannot use it. I have full admin rights and should be able to do all of the above so I need some developer advice or help on this issue.
