After upgrading my Nextcloud installation from 10.x to 12.01, I am seeing an error like the one described here: https://help.nextcloud.com/t/13986
In short, the background image and logo on the login page fail to load with the following errors:
Content Security Policy: The page’s settings blocked the loading of a resource at http://www.example.com/core/img/background.jpg?v=0 (“img-src https://www.example.com data: blob:”).
Content Security Policy: The page’s settings blocked the loading of a resource at http://www.example.com/core/img/logo.svg?v=0 (“img-src https://www.example.com data: blob:”).
Disabling the theming app causes the login page’s image and logo to appear correctly. I’d like to see if reverting the theming app to its “factory defaults” will clear this issue up, but I’m having trouble determining how to do so. I have tried removing (renaming) the theming app from the filesystem and then re-enabling it through the web admin console, but that simply throws the error “Could not download app theming”. I am at a loss on how to troubleshoot this further.
Nextcloud 12.01
Ubuntu 16.04 LTS
Apache 2.4.18
PHP 7.0