tried to add the mx records in my hosting website but i cannot receive emails.

Then tried to add a domain key and could not add it as well since "DomainKeys are not enabled, as the text record validation has failed."

When i send an email to my zoho account i receive the notice "The error that the other server returned was:

550-Please turn on SMTP Authentication in your mail client."

What am i doing wrong?

Best regards,