``` java.lang.IllegalArgumentException at org.briarproject.briar.sharing.SharingManagerImpl.sendInvitation(SharingManagerImpl.java:241) at org.briarproject.briar.android.sharing.ShareForumControllerImpl$1.run(ShareForumControllerImpl.java:71) at org.briarproject.briar.android.controller.DbControllerImpl$1.run(DbControllerImpl.java:37) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588) at java.lang.Thread.run(Thread.java:818) ``` * Android version: 6.0 * Phone model: SUNNY (V2502AN) * Briar version: 0.16.3 (531e555) * User comment: "Crashed when invited."