SMTPSenderRefused when access to less secure apps on gmail is turned on

I am getting this error:

(530, b'5.7.0 Authentication Required. Learn more at\n5.7.0  https://support.google.com/mail/?p=WantAuthError o187sm3117216qkf.26 - gsmtp',...)

I have access to less secure apps turned on, but I still get this error.

Does anyone know other ways of fixing this issue?

Thanks