My email provider is through GoDaddy as I have my own URL. The complete
verbatim message is as above with the exception of the date and who it was
addressed to. Where would I change a setting if I needed to?
The term, "URL" means, "Uniform Resource Locator", and has no meaning
outside of the context of defined protocols. "
http://www.example.org/" and
"are URLs. "
Www.example.org" is not a URL, but a
"Fully Qualified Domain Name" ("FQDN"). The "example.org" component is a
"Domain Name". Presumably, you have registered a domain name through
GoDaddy?
An SMTP 550 error is often (but not always) related to unauthorized
relaying. In the absence of any more detailed error than you have posted,
assume it indicates an unauthorized relay attempt; that is, you are trying
to use an SMTP server to relay mail for your domain, and that server is not
authorized as a relay for your domain.
If you are using GoDaddy for email hosting, you will need to learn how to
configure their server for your domain. It may be as simple as
authenticating to the server, using a username+password combination.