AsyncWebSocketClient | php异步websocket客户端 | Websocket library

I am trying to do something with ESPAsyncWebServer library. I have a class in ServerManager.h called MyServerManager. When I compile the code I get this error. What am I doing wrong? How can I fix it?

25:67 is the bold word "this"

src\ServerManager.cpp: In lambda function: src\ServerManager.cpp:25:67: error: 'this' was not captured for this lambda function request->send(LittleFS, "/status.html", String(), false, [this](const String &var) -> String { return statusProcessor(var); });

*** [.pio\build\nodemcuv2\src\ServerManager.cpp.o] Error 1

in ServerManager.cpp file