You don't appear to be checking your return values:

    # load session from db
    my $s = Mapps::Session->new();
    $s->load_session($sid);

    # session is good continue
    if (defined $s){
        $m->call_next;
    }
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I see nothing in load_session() which would undefine $s. Try this:

    # load session from db
    my $s = Mapps::Session->new();
    if (defined $s->load_session($sid)) {
        $m->call_next;
    }
[download]