Feedback Loops
Manage subscribers who report your emails as abuse using Feedback Loops (FBL). The mailbox provider forwards the reported message to a designated email address, allowing you to suppress or remove the complaining user from your database.
Overview
Feedback loops process spam complaints automatically:
+------------------+ +------------------+ +------------------+
| RECIPIENT MARKS | ---> | ISP SENDS | ---> | FBL ADDRESS |
| EMAIL AS SPAM | | COMPLAINT | | RECEIVES |
+------------------+ +------------------+ +------------------+
|
v
+------------------+
| PROCESSING |
| - Parse email |
| - Find contact |
| - Flag: Spammed |
+------------------+
|
v
+------------------+
| NO FURTHER |
| EMAILS SENT |
+------------------+
Why Feedback Loops Matter
Sender Reputation
- Reduce complaints - Stop sending to people who complained
- ISP compliance - Meet ISP complaint rate requirements
- Avoid blacklisting - High complaint rates trigger blocks
Legal Compliance
- CAN-SPAM - Honor unsubscribe requests
- GDPR - Respect recipient preferences
- Best practices - Industry standard for email senders
List Quality
- Automatic flagging - No manual intervention needed
- Clean lists - Stop emailing contacts who complained
- Better engagement - Focus on interested subscribers
How Feedback Loops Work
ISP Complaint Flow
- Recipient receives your email
- Recipient clicks "Report Spam" or "Junk"
- ISP records the complaint
- ISP sends complaint to registered FBL address
- Mumara processes the complaint
- Contact is flagged as Spammed and will not receive any further emails
Supported ISPs
Major ISPs that support feedback loops:
| ISP | FBL Program |
|---|---|
| Yahoo/AOL | Yahoo CFL Program |
| Microsoft | JMRP (Junk Mail Reporting Program) |
| Comcast | Comcast FBL |
| USA.net | USA.net FBL |
| Fastmail | Fastmail FBL |
| Others | Check individual ISP programs |
Gmail does not offer a traditional FBL program. Use Google Postmaster Tools instead.
Viewing Feedback Loops
Navigate to Setup → Feedback Loops to view all FBL addresses.
Page Features
- Add New button to create an FBL address
- Bulk Actions dropdown for batch operations
- Show entries dropdown to control page size
- Search box to find specific FBL addresses
Table Columns
| Column | Description |
|---|---|
| FBL Email | The email address receiving complaints |
| Complaints | Number of processed complaints (clickable to view details) |
| Status | Active/Inactive |
| Last Processed | Date and time complaints were last processed |
| Created on | Date and time the FBL address was created |
| Actions | Row action menu |
Row Actions
Click the ... (three dots) menu on any row to access:
| Action | Description |
|---|---|
| Edit | Modify FBL settings |
| Delete | Remove this FBL address |
Viewing Complaints
Click the Complaints number to view processed complaints for that FBL address.
Creating a Feedback Loop Address
Navigate to Setup → Feedback Loops and click Add New.
Feedback Loop Settings
FBL Email *
Enter the email address registered with ISPs for feedback loops.
Examples:
Use a dedicated email address solely for FBL processing. Register this address with each ISP's feedback loop program.
Hostname *
Enter the IMAP or POP3 server address.
| Provider | IMAP Host | POP3 Host |
|---|---|---|
| Gmail | imap.gmail.com | pop.gmail.com |
| Outlook | outlook.office365.com | outlook.office365.com |
| Custom | imap.yourdomain.com | pop.yourdomain.com |
Port *
Enter the server port number.
| Protocol | Port | Security |
|---|---|---|
| IMAP | 143 | None/STARTTLS |
| IMAP | 993 | SSL/TLS |
| POP3 | 110 | None/STARTTLS |
| POP3 | 995 | SSL/TLS |
Username *
The login username for the email account (usually the full email address).
Password
The password for the email account (stored encrypted).
Folder *
Specify the mailbox folder to check for complaint emails.
Default: INBOX
Validate Certificate
Select whether to verify server SSL certificates.
| Option | Description |
|---|---|
| Yes | Validate certificate (recommended for production) |
| No | Skip validation (use for self-signed certificates) |
Encryption
Select the connection security type.
| Option | Description |
|---|---|
| None | No encryption (not recommended) |
| SSL | Implicit SSL/TLS encryption |
| TLS | STARTTLS encryption |
Delete Emails after Processing
Select whether to remove complaint emails after they have been processed.
| Option | Description |
|---|---|
| Yes | Delete processed emails (recommended) |
| No | Keep emails in mailbox |
Recommendation: Enable to prevent duplicate processing and keep the mailbox clean.
Email Protocol *
Select the mail retrieval protocol.
| Protocol | Description |
|---|---|
| POP | Post Office Protocol |
| IMAP | Internet Message Access Protocol (recommended) |
Recommendation: IMAP is preferred for better message management.
Status
Toggle to enable or disable FBL processing. Inactive addresses are not checked for complaints.
Validating and Saving
Validate Connection
Click the Validate Connection button to test the settings before saving.
The validation checks:
- Server is reachable
- Credentials are valid
- Folder is accessible
- Protocol works correctly
Save
Click Save to create or update the FBL address.
Cancel
Click Cancel to discard changes and return to the list.
Processed Feedback Loops
When you click on the Complaints number in the FBL list, you see the Processed Feedback Loops page with details on feedback loops that have already been processed.
Page Features
- Show entries dropdown to control page size
- Search box to find specific complaints
Complaints Table
| Column | Description |
|---|---|
| No. | Row number |
| Contact ID | Associated contact record (clickable link to contact) |
| Email Address | The complaining contact's email address |
| User | Administrator who owns the contact |
| Campaign/Trigger | The campaign or trigger that caused the complaint (clickable link) |
| Complaint Time | Date and time the complaint was received |
| Message ID | Original email message ID for reference |
Navigating Complaints
- Click the Contact ID to view the contact record
- Click the Campaign/Trigger link to view the associated campaign or trigger
- Use pagination to browse through large numbers of complaints
Managing Feedback Loops
Editing an FBL Address
- Click Edit on an FBL address
- Modify settings
- Click Save
- Test connection to verify changes
Deleting an FBL Address
- Click Delete on an FBL address
- Confirm deletion
Changing Status
Toggle Status to enable or disable without deleting.
Registering with ISPs
Yahoo/AOL Complaint Feedback Loop
- Visit Yahoo's CFL (Complaint Feedback Loop) signup
- Verify domain ownership
- Register your FBL email address
- Wait for approval
Microsoft JMRP
- Visit Microsoft SNDS (Smart Network Data Services)
- Register your sending IPs
- Enroll in JMRP program
- Register your FBL email address
Other ISPs
Contact individual ISPs to inquire about their feedback loop programs.
Contact Flagging
How Complaint Processing Works
When a complaint is processed:
- Email address is extracted from complaint
- Contact is found in your lists
- Contact is flagged as Spammed
- Contact will not receive any further emails from the system
Spammed Status
FBL complaints result in:
- Contact status changed to Spammed
- Complaint reason recorded
- Timestamp logged
- All future emails to this contact are blocked
Contacts flagged as Spammed will not receive any further emails from Mumara. This protects your sender reputation and ensures compliance with ISP requirements.
Viewing Spammed Contacts
Navigate to Lists & Contacts → Suppression to see contacts flagged via FBL complaints.
Best Practices
Setup
- Dedicated address - Use only for FBL processing
- Register promptly - Enroll with ISPs before sending
- Test thoroughly - Verify connection works
- Monitor regularly - Check for processing issues
Complaint Management
- Act immediately - Process complaints in real-time
- Never re-add - Respect suppression permanently
- Track trends - Monitor complaint rates
- Investigate spikes - High complaints indicate problems
Prevention
- Permission-based lists - Only email opted-in contacts
- Easy unsubscribe - Prominent unsubscribe links
- Relevant content - Send what subscribers expect
- Proper frequency - Don't over-email
Monitoring
- Target < 0.1% - Complaint rate below 0.1%
- Check daily - Monitor complaint counts
- Segment analysis - Identify problematic segments
- Campaign review - Check complaints by campaign
Troubleshooting
Connection Failed
Possible causes:
- Incorrect server settings
- Firewall blocking connection
- Wrong credentials
Solutions:
- Verify server details
- Check firewall rules
- Test credentials directly
Complaints Not Processing
Possible causes:
- FBL status is inactive
- Cron job not running
- Wrong folder configured
Solutions:
- Enable FBL status
- Check system cron
- Verify mailbox folder
Contact Not Suppressed
Possible causes:
- Contact not found in system
- Email address mismatch
- Processing error
Solutions:
- Check if contact exists
- Verify email format
- Review processing logs
High Complaint Rates
Possible causes:
- Poor list quality
- Misleading content
- Too frequent sending
- Purchased lists
Solutions:
- Clean your lists
- Match content to expectations
- Reduce frequency
- Never use purchased lists
Complaint Rate Guidelines
Industry Standards
| Rate | Status |
|---|---|
| < 0.1% | Good - healthy sender |
| 0.1% - 0.3% | Warning - needs attention |
| > 0.3% | Critical - deliverability at risk |
Calculating Complaint Rate
Complaint Rate = (Complaints / Emails Delivered) × 100
Reducing Complaints
- Improve targeting - Send relevant content
- Honor preferences - Respect frequency choices
- Easy opt-out - Prominent unsubscribe
- Set expectations - Clear signup process
- Sunset inactive - Remove unengaged contacts
Next Steps
- Bounce Addresses - Configure bounce processing
- Suppression - View suppressed contacts
- Sending Domains - Configure domain authentication