It turns out it's a bug in iRedAPD-1.4.1. Fixed moment ago, thanks very much for your report and test.
https://bitbucket.org/zhb/iredapd/commi … b8bd026b1a
Please check above link for commit log, then fix file /opt/iredapd/plugins/sql_user_restrictions.py, restart iRedAPD service and try again. Let me know whether it works for you or not.