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Problems Sending E-Mail - Sending via port 587

UPDATED: October 22, 2013

If you are having problems sending e-mail or are receiving an error message which states something along the lines of "Cannot send outgoing mail due to Port 25 being blocked", this usually indicates a problem with your Internet Service Provider (ISP such as Verizon or Optimum) and NOT Bower Web Solutions itself.

What Is Port 25 and Why Is It Being Blocked?

To help control the amount of spam and viruses that originate from your ISP (Internet Service Provider, such as Optimum Online, Verizon, Comcast, EarthLink, etc.) your Internet Service Provider may start to implement outbound Port 25 (SMTP) filtering. More info on why port 25 may be blocked is on Verizon's website and on Optimum's website.

Their efforts will not protect your from being flooded with spam. To protect your e-mail account from spam, we suggest you take a look at our E-mail Defense Service.

How Can I Send E-mail if my ISP(Internet Service Provider) is Blocking Port 25?

Many ISP's (including the two biggest in Northern New Jersey and the New York Metro area, Verizon and Optonline) allow you to send e-mail using your outgoing account thru port 587.

Sending thru port 587

Sending thru port 587 is especially convenient for laptop users who use multiple ISPs.

If you already have your e-mail program (such as Outlook, Mac Mail etc) you do not need to recreate your e-mail account information again. You simply need to edit the existing account and change the SMTP server for the account(s).

If your ISP has enabled sending mail thru port 587 and you are on the Bower Web Solutions unix server (as opposed to our windows server. To check type in in your browser bar. Unix users will see a login screen or go directly to their webmail) to send via port 587 you need to:

  1. In the e-mail account you want to change, the incoming and outgoing mail server to
  2. Outgoing server should be the same as incoming server, and my outgoing server (SMTP) requires authentication should be checked.
  3. Outgoing server should be set for port 587.
  4. Use the following type of encrypted connection should be set for TLS or Auto.

Below is an example of changing an existing Outlook 2007 e-mail account configuration port 587 as the outgoing mail server.

  1. Go to the Tools menu and choose "Accounts..."
  2. From the Mail tab, choose your e-mail account double click on it " or "Change" button.
  3. In the following screen, change e-mail account window, Change the Outgoing mail (SMTP) server setting to:
    main screen outlok 2007 setup
  4. Click on the "More Settings" button tab and check that Outgoing server in Outgoing Server tab.
    • Outgoing server is 'same as incoming server is checked, and
    • my outgoing server (SMTP) requires authentication should be checked.
  5. In the advanced tab, change:
    • Outgoing server should be set for port 587. ., and
    • Use the following type of encrypted connection should be set for TLS or Auto.
      screenshot of outlook on how to change outgoing port
  6. Test account Settings (from the general tab or by clicking OK to return to the main window).

Outgoing mail not working while incoming mail is working is almost always an issue with your Internet Service Provider (and not an issue with Bower Web Solutions).

Information on setting up other mail clients using port 587 is on Verizon's website.

Alternatively, you can change your OUTGOING mail server (SMTP) from "" or "" to a SMTP mail server provided by your ISP. For more information, read how to send e-mail using your ISP's smtp server.

Be aware that many Internet Service Providers (ISP) such as Optimum Online, Verizon, Comcast are now cracking down of "spam activity". These ISPs are now limiting how many e-mails you can send out from your computer's location within a given time period and may suspend your ability to send e-mail if you are sending more than 30 recipients at a time or more than 50 separate e-mails within an hour.

If you plan to send large numbers of mass e-mails to your client base, you really need to consider a separate service such as Constant Contact. For less than 75 cents a day, you can take advantage of advanced e-mail tracking features and sleep at night know that your web site or web server will not be "blacklisted" by the major ISPs! Click on the image below to get your FREE Constant Contact account now!

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