Hello @Sandy
Nice to hear from you again.
The law you are looking for is Aufenthaltsgesetz (AufenthG) §12a (https://dejure.org/gesetze/AufenthG/12a.html). It says that Wohnsitzauflage has to be removed if you start a job that is subject to social insurance contribution. You have to work at least 15 hours a week and earn a minimum of 710€. You have to go to Ausländerbehörde and show them your work contract in order to prove that you started such a job.
Ausländerbehörde also has to remove it if you start studying or if you start an Ausbildung.
Best regards,
Thorgen