Why doesn't connect work in Qt?

Question

Qt

Why is the connection not working? Writes candidate expects 1 argument, 0 providet;

connect(this->findChild<QPlainTextEdit*>("plainTextEdit"), 
         &QPlainTextEdit::textChanged, this, [=](QString str){
             Bus::Instance().setMessage(str.toStdString());
 });

Answer 1

this is not needed.