How to Prevent Your Constant Contact Emails From Being Blocked

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How to Prevent Your Constant Contact Emails From Being Blocked

If you believe your email campaigns are being blocked by an ISP or mail server as opposed to being filtered, we suggest you start by reaching out to your subscribers (contacts) or their ISP (Internet Service Provider) directly.

If numerous subscribers from the same large domain (such as Gmail, Hotmail or Yahoo) or ISP (Comcast, Road Runner or Verizon) are appearing in the “Blocked” bounce category in your account, please contact the Constant Contact telephone support team directly so they can take steps to resolve the issue.  Constant Contact’s ISP Relations Team has experience working with these large providers and will work to resolve the problem on your behalf.  They can be reached at 781.472.8103

For smaller ISPs and domains Constant Contact have created the following letters to help you communicate with your subscribers and their ISPs.  Once the letters have been handed off, Constant Contact’s ISP Relations Team will work with the appropriate individuals to resolve the issue.  The ISP Relations Team is available (via the address included in the letter) should the ISP/Domain require follow-up information such as mail logs.  While working with Constant Contact on this issue, we have found this approach usually yields much faster results since the admins are hearing from their own users who want the mail.

Important: When you copy and paste these letters into an email sent via your standard email and not through Constant Contact, please be sure to replace the XXX placeholder with more specific and appropriate information before sending it to either the contact or ISP.

Letter You Send to Your Subscriber

To: Contact
Subject: Contact Your ISP


I am emailing to alert you that your ISP is blocking the newsletters/promotions/announcements you have subscribed to receive. I know that you would like to receive these valuable communications, so I ask that you send the attached letter to your ISP’s customer support department. Please be sure to replace in the (YOUR NAME HERE) areas below.

As you may know, Constant Contact powers the email communications I send. When you receive a response from your ISP, please forward the response email to the following address: The Operations Department at Constant Contact will follow-up with your ISP once they receive your email.

I apologize for any inconvenience this may cause you.


Letter Your Subscriber Sends to their ISP

To: ISP Customer Support
Subject: Remove Constant Contact Block

Hello. My name is (YOUR NAME HERE) and I have been a customer of your services since (LIST YOUR DURATION OF SERVICE HERE). I understand that you employ filters and/or blacklists to protect customers like myself from unsolicited email; however, this has made it impossible for me to receive newsletters, announcements, and promotions that I have requested. I value these communications and would like to receive them using this email address.

The sender of these emails uses an email marketing service called Constant Contact. Constant Contact is not an open relay and has strict anti-spam policies in place. Because your filters block emails from Constant Contact I am unable to receive these communications.

I ask that you please help me determine why these emails are being blocked. For further information about Constant Contact or to request more information from them such as log files, the Operations team can be reached at – 781.472.8103 or

Mail from Constant Contact can be found by the following characteristics for whitelisting:

“Envelope from:” domains:

Sending IPs:

All mail from Constant Contact is sent from:

IP Range: –

Specific IPs sending from this range:

Please contact me when this problem has been resolved.


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