a 'AddPublisher' state was sent from poe at 13 to session 2, but session 2 has neither that state nor a _default state to handle it POE::Component::Server::TCP->new( Alias => 'TCPServer', ... InlineStates => { AddPublisher => sub {} } ; $_[KERNEL]->post( TCPServer => AddPublisher => $_[SESSION], 1 ); }, #### sub POE::Kernel::ASSERT_DEFAULT () { 1 } use POE qw( Session Component::Server::TCP ); POE::Component::Server::TCP->new( Alias => 'TCPServer', Port => 53511, InlineStates => { AddPublisher => sub {} }, ClientInput => sub {} ); POE::Session->create( inline_states => { _start => sub { $_[KERNEL]->post( TCPServer => AddPublisher => $_[SESSION], 1 ); }, _stop => sub {} } ); POE::Kernel->run;