My visual editor setup was working fine this afternoon, but then I started getting this error whenever I tried to use the editor: Error loading data from server: apierror-visualeditor-docserver-http: HTTP 500. I tried installing php7.2-curl (didn't work), so I decided to dive into the logs. There I found the following error: Template Fetch failure for \"Main_Page\": 500. I couldn't find anything on Google so I came here. The only thing I can think that might have caused it was me setting up Wikibase in preparation for importing some infoboxes from Wikipedia.
My setup: NodeJS 12.16, Mediawiki 1.34 (Bitnami edition), Ubuntu 16.04 LTS. AWS EC2 instance.