We are getting a send email error as follows:
= = = = =
SMTP Error: The following recipients failed: 200mph@200mphmedia.net
SMTP server error: Verification failed for
550-No Such User Here
550 Sender verify failed
= = = = =
The smtp mail server is correctly identified for the custom mail server settings.
Cannot use internal phpmail because we are sending attachments to the emails being sent.
Any troubleshooting suggestions to resolve this?