When signing in to Limn at http://reportcard.wmflabs.org/ using OAuth you initially get redirected to http://localhost:5000/auth/mediawiki/callback which probably doesn't exist on the users' machine.
It also identifies itself on meta-wiki as "MediaWiki OAuth Example Consumer"
Declining this Analytics-Visualization task, as this project tag was used for Limn. Limn has been superseded by Dashiki.
If this task still makes sense in terms of Dashiki, then please file a new task tagged with Data-Engineering-Dashiki (or reopen and update this task plus update the project tags of this task).
Thanks a lot! (Reference: T274647)