Confirmed, and thanks for the patch Florian. I'm going to do the test a little differently though because this is a bug in the lower level API, specifically mailman.app.membership.add_member(). It affects more than the REST API so I'm going to create a new unittest in mailman/app. ** Changed in: mailman Status: New => Confirmed ** Changed in: mailman Importance: Undecided => Medium ** Changed in: mailman Assignee: (unassigned) => Barry Warsaw (barry) ** Changed in: mailman Milestone: None => 3.0.0a7 ** Summary changed: - REST API: Subribing to more then one list raises AssertionError / returns HTTP 500 + Typo in add_member() prevents subscribing an email already linked to an existing user ** Changed in: mailman Status: Confirmed => Fix Committed -- You received this bug notification because you are a member of Mailman Coders, which is subscribed to GNU Mailman. https://bugs.launchpad.net/bugs/710182 Title: Typo in add_member() prevents subscribing an email already linked to an existing user