Your SMTP server settings appear to be correct. There is nothing to worry about if you have error 550, the script will resend the email later.
You can also try to resend the email manually.
If the email status shows as 'error', please wait about 20 minutes before clicking the 'resend' option.
The script can also send email without an SMTP server. You can turn off SMTP server by un-checking the 'Use SMTP' option in Main Config, from the Admin.