Today, when configuring Xdebug under phpstrom, installing online tutorials is configurable and can not be executed during single-step debugging. The error prompt is waiting for incoming connection with IDE key XXXXXXX. After various attempts to modify it, I finally found out the reason. The original environment I used was phpstudy, which is divided into three parts. There are two service modes: system service mode and non-service mode. I use the latter. The guess is that phpstrom failed to find session ID in Apache in the system, so it reported the error. After changing to system service, this problem has been solved, which is recorded here.