How to fix Arduino error: ‘class HardwareSerial’ has no member named ‘prinln’; did you mean ‘println’?

When you see the following error message:

error: 'class HardwareSerial' has no member named 'prinln'; did you mean 'println'?

You have a typo in your code: You are trying to call prinln() but you’re missing the t in println(). Add the t so you’re calling println() and retry compiling your project.