This article is about Cloudflare Rocket loaders passion to break Nextcloud (and apparently PhpMyAdmin for some people) and how to fix it.
I have installed Nextlcoud for some testing purposes some time ago. As a side note; Yes, I’m using Cloudflare for DNS. And was surprised by Nextcloud’s clean UI, consisting of only the logo and a background image.
I know one of the last updates overhauled Nextclouds UI, but this is a little too clean, even in my taste. To diagnose the issues I swiftly opened the Javascript console hidden away in the inspect element dialogue. One of the major error messages I saw was the browser being unable to load a library called “RocketLoader”. After some searching, I found out that others have also run into this problem before, but Nextcloud does not use RocketLoader. After going through Cloudflare’s Speed setting in boredom one day I saw an option titled “Enable Cloudflare Rocket Loader”, which was enabled. I turned the ticked box off, and yes a few minutes later Nextcloud worked again!
Tl;Dr
Go into your domains Cloudflare setting, then choose Speed and go to “Optimization”, disable the Rocket Loader™ option. Your service should start working properly again.
Thanks, that helped! A shame, that cloudflare doesn’t check their optimizations for compatibility with such popular projects.