Yet another 550

Hi,
I have recently set up a domain and pointed the MX records correctly. I can send email but if someone tries to send me one they get a message not delivered.

The response was:

550 Please turn on SMTP Authentication in your mail client. mail-wm0-f45.google.com [74.125.82.45]:35379 is not permitted to relay through this server without authentication.

Could you confirm for me that this is just because the DNS change hasn't propagated to your servers yet?

https://mxtoolbox.com/SuperTool.aspx?action=mx%3ayellowcherrysolutions.co.uk&run=toolpage

Thanks,