This is because your method name you are passing in selector is wrong. You need to add colon : at submitLogout:
suffix
Use
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(submitLogout:) name:@"logoutInitiated" object:nil];
in place of
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(submitLogout) name:@"logoutInitiated" object:nil];
Hope it helps you.