Seems you are already opted out of the insider program.
The build that you are running (19043.1237) is a stable build.
No need to worry, you aren't in the insider program.
Then too, open Settings and go to Privacy > Diagnostics and feedback
Then go to the Windows insider program settings page and see if you can opt out.
Regards,
What schould i do if i cannot change this?
It says that its manged by the organisation (windows Insider program)