Code Review broken in Web IDE

Project: All projects, including https://gitlab.com/the-hatchery/vestedin/ui and https://gitlab.com/the-hatchery/vestedin/api Issue: I cannot review merge requests in Gitlab.com. Web IDE reports an error: "Error setting up editor. Please try again". I see that there is an issue with an AJAX request. Please see video: https://monosnap.com/file/9ZCWVJt3yLPoJBDrpAbJ3TrzIufkxx

Steps to Reproduce:

1. View merge request - https://gitlab.com/the-hatchery/vestedin/ui/merge_requests/2
2. Click "Open in Web IDE". This opens the Web IDE with the relevant files in tabs.
3. Click any tab, and it fails with error. You may remove this text before creating your issue. Please provide the following information when creating support requests for GitLab.com.