NFN E-mail service overview

Naples Free-Net Email Services

NFN has developed various policies and procedures to protect our customers from abuse. This site has been developed to give bulk email senders, ISPs, email service providers, postmasters, and domain administrators a location from which to learn about these policies and the necessary steps required to resolve problems. If you were directed to this site because of a specific error received when trying to send an email please find the error listed below for additional information and troubleshooting tips to resolve the issue.


If you attempt to repeatedly log in to an NFN account with incorrect login name or login password, the NFN email server system will interpret that as a hacking attempt on a user account.  The end result is that the NFN mail server will not accept any more connection attempts from your specific IP origination.  This automatic timed restriction may remain in place for up to 20 minutes or more depending on the protocol method or speed of the abuse behavior.

Make sure you are properly using your correct username and password for your NFN account.  If in doubt, call the NFN HelpDesk during regular business hours and get help.

General Information

All NFN Email customers are limited to a maximum single message size of 35 megabytes.
All the available NFN Account mail services are listed here.

Webmail (a Premium Account service):  Direct your browser to
The Webmail is also accessible via the NFN Home Page by clicking on the left menu item “Connect to Web Mail” link.

Mail Client Server Settings (Outlook, Outlook Express, Mozilla Thunderbird, Eudora, etc):
Incoming mail server =
Outgoing mail server =
If you want to use the remote SMTP/POP setup, see here.

Webmail Error Codes
Error – Authentication Failed:
Make sure when you log in to NFN WebMail that you use your correct username (the part before the “” in your NFN email address) and the correct password (case sensitive).   You must be a Premium Account holder to use the NFN WebMail.

If having a problem, make sure you erase everything in the username and password boxes and type in the information again.
Pay attention to any alert messages when you log in.  An excessive amount of emails in your email box can cause slow performance or other problems.

SMTP Error Codes

  • 421 Connection Refused – Incoming mail sender exceeded the maximum number of messages allowed per delivery attempt. Rate limiting applies when originating outside our network.
  • 421 Service Not Available – Incoming mail sender may be on an NFN blacklist or spam list.
  • 421 Lost – Connection was terminated  – Possible network connectivity issue.
  • 450 Unable to find: Domain not found
    Please verify the recipient’s domain name email address is valid.
  • 452 Too many recipients – The number of email recipients per message exceeded the allowable threshold.
    You can only CC or BCC 50 addresses in a single email
  • 503 Sender Already specified – Too many invalid email addresses
  • 550 Message identified as SPAM
    The email was flagged as spam by the NFN SpamFilter anti-spam detection system. NFN also uses several different tactics to determine if a message is spam. The primary tactic is using an industry leading anti-spam filtering application, corroborating feedback from the Internet community and NFN subscribers. A message will not be accepted by our mail servers if it is flagged as spam.If you are using your NFN SpamFilter, check your “last 40” spam marked emails.  Add an appropriate email address or email domain to the bypass settings to avoid future miss categorizing.
  • 552 Message size exceeds allowed maximum message size:
    20 Megabytes is the maximum allowable single message size for NFN email customers. The total includes the message and the attachment(s).

Common Email Service Questions

Why won’t Outlook Express download all my e-mail on dialup?

Dialup cannot easily handle downloads of large sizes such as photos or movies over 1000 kb and you may have allowed your mailbox to collect several megabytes of data.  If you receive many large files, you may want to consider high-speed Internet such as NFN DSL.  If you have a premium account, you can use Webmail to look at your messages and delete the large ones.  (Be sure to log out after deleting them or they will not be permanently deleted.)  You should then be able to download the rest of your messages in Outlook Express.  If you have a standard account, Webmail is not available.  Standard account users will have to call the NFN Helpdesk and ask them to delete all your e-mail on the server through our e-mail repair program (they cannot selectively delete only large messages).  Standard account users may also wish to use another mail webpage service such as to view their e-mail and delete large messages.  Dialup users may wish to set up a mail rule in Outlook Express to automatically delete large messages before downloading.  See our FAQ “Outlook Express  mail size restrict” at for instructions.

What is rate limiting?

Rate limiting is an anti-abuse network protection method. To prevent spam and virus traffic, the NFN mail complex limits the number of messages and recipients per hour on inbound and outbound mail. This policy is standard industry practice. The rate limit threshold is a dynamic number configurable by system administrators and has been set in accordance with standard industry practice. Rate limiting ensures mail system stability and usability for all NFN customers.
Suggestions to work with rate limiting thresholds:

Wait 5 minutes to send additional emails.  The system will learn your remote IP and email address and automatically exempt you from future sending rate limits.
Break up the number of recipients into smaller groups.
How does NFN determine email is spam?
NFN uses several different tactics to determine if a message is spam. The primary tactic is using an industry leading anti-spam filtering application, corroborating feedback from the Internet community and NFN subscribers. A message may not be accepted by our mail servers if it is flagged as spam.

What is mail relaying and does NFN allow this practice?

Mail relaying is the practice of using NFN mail servers to send mail (SMTP) from non NFN IP space or from domains not hosted by NFN. Relaying is not allowed by NFN. If an NFN customer is using their laptop outside the NFN network, they should direct their browser to  and click on the green “Read Email on the Web” link, or change the outgoing mail server setting on their mail client to match the outgoing mail server of the service provider they are using. NFN does provide a very useful alternative that solves most remote email uses for NFN Accounts and is discussed here.

Am I allowed to send mail from non NFN IP space using webmail?
Yes. WebMail, which is a browser based email interface, works like a web page.

How can NFN customers report spam?

Email spam problems are sent to the NFN Administrator and will be addressed to improve filtering. The filtering data used in determining what email is flagged as spam by NFN’s anti-spam system is automatically updated based on many factors, including NFN SpamFilter use.  Please contact the NFN HelpDesk if you need help with a spam problem.

How can NFN customers report a message being incorrectly treated as spam (false positive) when trying to send an email?
If you receive an error when trying to send an email that indicates the message was spam, you may contact the NFN HelpDesk for guidance. Please make sure that you do not have other problems, such as an infected PC or incorrect sending email address.  The NFN mail server will reject any originating mail that contains a virus.

Leave a Reply

Your email address will not be published.