error - 550 authentication turned on in your email client

[Church Office]

In trying to send out a mass e-mail I keep getting a message stating that the
email could not be sent because one of the reipients was rejected by the
server. The server response is 550 authentication turned on in your email
client.

The computer that uses this is running Outlook 2000 on Internet explorer 6.

 

[Roady [MVP]]

Turned on or turned off? Usually this needs to be turned on or is "on"
(read: allowed) by default when you are on the same network as the ISP
hosting the email account.
Also ask your ISP if you are allowed to send that many emails at once.