Feedback Loop (FBL) - Online Help | Zoho Campaigns

Feedback Loop (FBL)

A feedback loop (FBL) is a process for listing spam complaints from your sent email campaigns. Some inbox providers such as Yahoo!, Outlook, and AOL send feedback on spam complaints to the email marketing services responsible for the campaign. 

How FBL works

When a recipient marks an email as spam, this is considered a "complaint". Inbox providers block future emails from that sender from reaching the recipient's inbox. Not all inbox providers send feedback on spam complaints in the form of an FBL. 

As Zoho Campaigns is the sending platform for your messages, we receive the complaints and remove those addresses from your mailing list. The campaign report you receive from Zoho Campaigns includes the complaint rate based on the FBLs from various inbox providers. We suggest you take note of complaints in every campaign report and aim to maintain a complaint rate below0.1%


  1. To maintain good mailing list hygiene.
  1. To help you identify any issue in your mailing practices and tackle complaints.
  1. To track your contacts' behavior.

Some inbox providers who offer FBL

  1. AOL

  2. Zoho Mail

  3. Yahoo!

  4. Outlook

  5. BlueTie

  6. Comcast

  7. Cox

  8. Centrum

  9. Earth Link 

  10. FastMail

  11. La Poste

  12. Mail.Ru

  13. OpenSRS (Tucows)

  14. Locaweb

  15. Synacor

  16. Seznam

  17. Terra Mail

  18. Telenor

  19. XS4All

  20. Italiaonline

  21. United Online

  22. USA.NET

  23. UOL Brazil


Gmail doesn't offer an FBL service but does provide the Postmaster tool to track spam complaints. If you have recipients using Gmail, you can use this tool to examine your email sending practices and identify reasons for delivery failures. 


Only a few inbox providers offer FBL reports. This does not mean there are no complaints from contacts using non-FBL providers. Avoid falling into the common misconception below.

Myth: My campaign report has a complaint rate less than the threshold, so I don't have any spam complaints. 

Reality: You may still have complaints from contacts using non-FBL providers. If your list has only contacts using non-FBL providers, then you will always have a zero complaint rate in the campaign report regardless of how many complaints are made. You can follow our best practices on how to maintain good mailing list hygiene.

FBL from inbox providers can be helpful to analyze your mailing list and sending practice. So, we recommend that you pay attention to our campaign reports and take measures to reduce the complaint rate.

    Zoho CRM Training Programs

    Learn how to use the best tools for sales force automation and better customer engagement from Zoho's implementation specialists.

    Zoho CRM Training
      Redefine the way you work
      with Zoho Workplace

        Zoho DataPrep Personalized Demo

        If you'd like a personalized walk-through of our data preparation tool, please request a demo and we'll be happy to show you how to get the best out of Zoho DataPrep.

        Zoho CRM Training

          Create, share, and deliver

          beautiful slides from anywhere.

          Get Started Now

            Zoho Sign now offers specialized one-on-one training for both administrators and developers.

            BOOK A SESSION

                        Still can't find what you're looking for?

                        Write to us:



                          Manage your brands on social media

                              Zoho Marketing Automation

                                Zoho Sheet Resources


                                    Zoho Forms Resources

                                      Secure your business
                                      communication with Zoho Mail

                                      Mail on the move with
                                      Zoho Mail mobile application

                                        Stay on top of your schedule
                                        at all times

                                        Carry your calendar with you
                                        Anytime, anywhere

                                              Zoho Sign Resources

                                                Sign, Paperless!

                                                Sign and send business documents on the go!

                                                Get Started Now

                                                    Zoho SalesIQ Resources

                                                        Zoho TeamInbox Resources

                                                                Zoho DataPrep Resources

                                                                  Zoho DataPrep Demo

                                                                  Get a personalized demo or POC

                                                                  REGISTER NOW

                                                                    Design. Discuss. Deliver.

                                                                    Create visually engaging stories with Zoho Show.

                                                                    Get Started Now

                                                                                          • Related Articles

                                                                                          • Unsubscribe Feedback

                                                                                            Ask your contacts why they unsubscribe from your newsletters by showing them a simple poll. A poll with different feedbacks that your contacts can select. To enable Unsubscribe feedback: From the navigation toolbar, select Settings and choose Signup ...
                                                                                          • How to use Google Postmaster Tool to boost your Email Deliverability

                                                                                            Mailbox providers consider the reputation of your sender domain when making inbox decisions. If your sender domain has a negative reputation, your emails may land in the spam folder. If your sender domain has a positive reputation, the chances of ...
                                                                                          • Getting started with email deliverability

                                                                                            Identifying the needs and interests of contacts and conceptualizing email campaigns around those are part and parcel of a marketer's daily routine. Sometimes marketers may assume that crafting a compelling campaign alone will help them hit their ...
                                                                                          • How to delete the Zoho Campaigns account in an iOS device?

                                                                                            You can delete your Zoho Campaigns account in iOS devices by following these steps, Open Settings in Zoho Campaigns app. Scroll down and select Delete Account. Click Proceed. Click Next. Choose a reason and add feedback. Click Agree to delete account ...
                                                                                          • How email engagement magically boosts inbox placement

                                                                                            Mailbox providers such as Gmail, Yahoo!and others have been validating a lot of data points like spammy content, email engagement, and user interests to offer inbox placement —i.e. the number of emails that actually reach an inbox as opposed to ...
                                                                                          Wherever you are is as good as
                                                                                          your workplace



                                                                                            Watch comprehensive videos on features and other important topics that will help you master Zoho CRM.


                                                                                            Download free eBooks and access a range of topics to get deeper insight on successfully using Zoho CRM.


                                                                                            Sign up for our webinars and learn the Zoho CRM basics, from customization to sales force automation and more.

                                                                                            CRM Tips

                                                                                            Make the most of Zoho CRM with these useful tips.

                                                                                              Zoho Show Resources