pretty-permalinks
Ensure pretty permalinks is enabled.
Install
This checkers comes with the preflight-command package. No extra setup steps needed.
Config
WARNING
Changing this checker's config doesn't make sense. Use with caution!
# disable it
[pretty-permalinks]
enabled = false
Solution
TIP
You might need to change web server(Nginx / Apache) settings. See WordPress Codex
Use any option but Plain.