In a self-hosted OpenProject 14.x instance (Ubuntu 22.04, using the packager installation) where can I disable user self-registration feature? As an OP admin practically every day I have to handle unwanted registration attempts by spam robots or hackers.

Hello Istvan,

that can be handled at the administration section. Navigate to Administration -> Authentication to adjust how users can register at your OpenProject installation.
Please find here a detailed guided that explains each available registration option:

https://www.openproject.org/docs/system-admin-guide/authentication/authentication-settings/#general-authentication-settings

Best,

Alexander

Thank you. I have fond it.