If you get the following error when trying to send emails:
421, response: Unexpected failure, please try later
This is usually a temporary issue. If the error is different such as:
"No action is required on your part. Delivery attempts will continue for some time, and this warning may be repeated at intervals if the message remains undelivered. Eventually the mail delivery software will give up, and when that happens, the message will be returned to you."
this could indicate a problem with the receiving server.
If you are experiencing this error everytime you try to send an email, please contact us so we can test your email client settings.