I get that error while saving my content, after changing the workflow of an existing form.
It prevents me from saving the content.
java.lang.NullPointerException at org.ametys.cms.repository.RequestAttributeWorkspaceSelector.getForcedWorkspace(RequestAttributeWorkspaceSelector.java:67) at org.ametys.plugins.wantad.WantadFunction.execute(WantadFunction.java:145)