Too Many Recipients?

For those who regularly use distribution lists for managing and sending e-mails, receiving an error message can be a nightmare. One of the most common errors that is received is the “452 4.5.3 Too many recipients" notice. This error is returned to the sender to indicate that a distribution list is too big, but where is the message coming from and what does 452 4.5.3 mean? Also, how many is too many recipients?

A common misconception of Outlook users is that this error message is sent by Outlook when a distribution list is too large. In actual fact, the message is sent by the Internet Service Provider (ISP) you are using, or if you are within an office, the error message is usually sent by the corporate mail administrator. Outlook itself does not have a limit on the number of contacts you send an e-mail to, it is the limits place by the ISP or mail administrator that generate the error message.

The reason these limits are set is to protect against users sending spam e-mails. If you have too many names on a list, your e-mail may be marked as spam and treated as such. Since distribution lists are sending the exact same message to a large number of recipients, the spam filter will likely pick up on that message and mistake it for junk mail.

As most of us are all too painfully aware, “spam” can be categorized as any message distributed to users in mass quantities – in other words, the online version of junk mail that many of us receive in our home or work mailboxes. Even the most inexperienced web surfer has seen some version of spam, and most of us are savvy enough to ignore these messages completely, delete them or install a spam filter that will help to separate the spam from the legitimate messages.

The easiest way to prevent this message from popping up is to create distribution lists with a reasonable amount of e-mail addresses –less than 25 recipients if possible, although your server may allow between 50 - 75 recipients on each list. You can find out the limits for sending e-mails by contacting the mail administrator or your ISP. By saving a number of distribution lists with less than this number of contacts, you should avoid receiving this error message the next time you send mass emails.

By the way, the 452 4.5.3 code is just a signifier of the type of error. Some people may receive just a 452 error or a 4.5.3 error, but both mean the same thing, your e-mail was bounced back because those recipients were over the limit allowed by your account.