554 Transaction Failed 554 5.0.0 Service Unavailable 554 Transaction Failed Error When Sending An Email?

554 Transaction Failed Error When sending an email? - 554 transaction failed 554 5.0.0 service unavailable

I get an error 554 transaction failed when sending e-mails for 2 people. I get e-mails to another 100 people with no errors.

You can to me, but I get the error response to me a few seconds.

The error message reads as follows:

----- The following addresses had permanent fatal errors -----
\\ \\ \\ \\ \\ \\ \\ \\ U0026lt; emailaddresshere>
(Reason: 554 Transaction Failed)

----- Transcript or session follows -----
... while talking to smpt.recipientsserver.com.:
\\ \\ \\ \\ \\ \\ \\ \\ U0026lt \\ \\ \\ \\ \\ \\ \\ \\ u0026lt \\ \\ \\ \\ \\ \\ \\ \\ u0026lt; 554 Transaction Failed
554 5.0.0 Service unavailable

I replaced the e-mail and an SMTP server to protect the innocent ")