Error with compiling sketch to arduino

When i copied the sketch then i pasted it
arduino didnt identify the following
Cayenne.virtualWrite(0, millis());

Cayenne.begin(username, password, clientID);

Have you added the cayenne MQTT library? is the latest arduino IDE you are using?

yes i have added it

maybe it is issue with the arduino ide version. Can you install Arduino IDE 1.8.15

thanks for the awesome information.